Chapter XIX · LEAD AND ITS COMPOUNDS (continued 2)

Tinning and enamelling of the hollow ware used for culinary and domestic purposes is an industry confined for the most part to Wolverhampton, Bilston, and Dudley. The iron kettle or saucepan about to be tinned is first cleaned or prepared by being swilled in a mixture of dilute hydrochloric acid and chloride of zinc. The process of tinning consists in dipping the utensil into a trough containing molten tin and lead in the proportion sometimes of 60 per cent. of metallic lead and 40 of tin. Owing to tin being the more expensive metal, the cheaper ware is often dipped in a composition of 70 per cent. of lead and 30 of tin. The dangers incidental to tinned hollow ware are twofold: first, if the workman who dips the utensil in the molten lead is not careful, cleanly, and temperate as regards the use of alcohol, he may suffer from lead poisoning; and secondly, the poorer working classes, who buy the cheaper ware, which has been nominally tinned but is in reality leaded, also run the risk of becoming poisoned by the food either having become contaminated by lead in the act of cooking or subsequently. When the cauldrons containing the molten metal, into which the workman plunges the pans, etc., are hooded, the fumes are not so readily inhaled. It is a common belief among these men that the poison enters the system when they are wiping off the metal from the hot sauce-pans, etc., by means of tow. In the white enamelling of iron hollow ware many manufacturers are now using a leadless glaze with every promise of success.

The enamelling of copper letters or tablets is shown by Dr Legge to be a source of plumbism. Four cases were reported to the Home Office in 1900. The danger occurs during the “brushing on” and “wooling off” of a black enamel powder, which was found to contain as much as 67.0 per cent. of lead.

Electric Accumulator Works and Lead Poisoning.

The manufacture of electric accumulators for telegraph and telephone purposes and for motor cars has become a very important industry, and is likely to become still more important as time goes on. There is one process in the manufacture which is distinctly dangerous. The workmen who rub the red lead, made into a paste by means of dilute sulphuric acid, on to embossed or perforated plates occasionally suffer from plumbism. When the plate leaves the workman its interstices look as if they were filled with red clay. Both sides of the plate have to be treated by the workman, whose hands are generally covered with indiarubber gloves. During the mixing of the dry red lead or litharge with the dilute sulphuric acid a considerable amount of dust is created. The indiarubber gloves which are worn by the men who fill the perforations in the plates with the lead paste become in time thin and worn, or they get torn, and as a result certain parts of the hands of the men become coated with the red composition. By this means, as the work entails a considerable amount of friction, lead poisoning may readily occur. In visiting electric accumulator works, I found several of the workmen, especially the younger men, extremely pale, and suffering from headache; some of them had been laid off with colic, and they presented a well-marked blue line on their gums.

The colic of electricians is not a new disease. In one electric accumulator works in La Hague in 1894, there occurred 37 cases of plumbism in 252 male workers; and in another factory in Wiesbaden 12 cases of lead poisoning occurred in 90 workers. Of 30 patients suffering from lead colic admitted into the Hospital Bichât, Paris, during 1899, Talamon says more than one-half were electricians, the remainder being made up of painters, plumbers, and typographers. So prevalent had lead poisoning become in Germany that the Imperial Health Office directed an inquiry[63] to be made into the conditions of labour in electric accumulator works. In consequence of this, special rules were issued, and as these now govern the industry in Germany, it will not be out of place if I quote at some length from the Report, a translation of which has been kindly placed in my hands by Dr Morison Legge. The information embodied in the Report was collected by a circular letter of the Chancellor, and deals with the extent of the manufacture of accumulators and the dangers of working. From one factory alone the following particulars were received as to the special incidence of plumbism in particular processes.

Occupation. Number Employed. Number of Cases of Lead Poisoning. Per cent.

Casting 30 3 10.0

Pasting 30 9 30.0

Soldering 16 6 37.5

Trimming 30 4 13.3

Plumbing 30 9 30.0

Section Building 60 5 8.3

As regards remedial measures, special attention was directed to: (1) casting and preparation of the plate; (2) mixing the paste; (3) actual pasting; (4) the drying and building into batteries of the various segments; (5) forming and changing plates. As regards these various headings the information gathered is as follows:—

(1) Ordinary lead, often containing a trace of antimony, is used for casting the plates. From the surface of the lead in the melting pots fume rises (oxide of lead), so that it is recommended to have the melting pots arranged that they can be provided with an efficient hood and shaft leading either into the open air or into a chimney. The need for these precautions lies in the fact that not only are the fumes of lead and antimony harmful when inhaled, but commercial lead often contains traces of arsenic, varying from 0.1 to 7.9 per cent.

(2) Litharge and red lead are used for making the paste, and as these come to the works in casks, the dry material is transferred from the cask to the worker’s bench by means of a shovel or trowel. Dust thus becomes scattered about in all directions. It is, therefore, desirable to have the floor of the workrooms moistened and swept daily. The mixing of the red lead and sulphuric acid should be done in a closed chamber or under an exhaust shaft.

(3) As regards the wearing of gloves by the men who paste the plates, reference is made to the difficulty of keeping the gloves in good repair. The same difficulty, as I have already mentioned, occurs in Britain. In some of the electric accumulator works the gloves worn are too short. The dry red lead occasionally gets inside the gloves, and as these tend to keep the hands hot and cause them to perspire, plumbism is rather encouraged than prevented, or skin eruptions develop. In order to avoid, therefore, as far as possible absorption of lead by the skin, two alternatives are put forward by the German Committee of Enquiry: (a) the work is not to exceed eight hours a day, to be broken by a pause of at least one and a half hours; or (b) there is to be one six-hours’ spell of work in the day. The Committee is in favour of the latter. Respirators for the men engaged in pasting are not considered necessary.

(4) In building up the batteries by means of solder, ordinary solder is not used, but a very pure lead instead, in order that the connections made between the plates may not be affected when they are subsequently exposed to the acid. To bind these plates together by solder, the heat from an oxygen or hydrogen blow-pipe flame is used, but frequently the temperature reaches a height sufficient to cause volatilisation of the lead, and statistics show that persons engaged in this occupation run a considerable risk of lead poisoning.

(5) Opinions were found to differ as to the effect of the dilute sulphuric acid vapour in the formation-room upon the workers. There was said to be medical testimony as to its good effects upon workpeople, who are the subjects of chronic bronchitis. Reference is made to the difficulty of providing fans for ventilation of these rooms owing to the deleterious action of the acid upon the metal contained in the fan, and yet some form of artificial ventilation is necessary.

The method adopted in the factory of determining the presence of lead in the air was the simple one of suspending, at the level of the worker’s head, a sheet of blotting paper, 100 centimetres square, previously moistened. Subsequent treatment with dilute acid and exposure to the action of sulphuretted hydrogen showed whether lead was present or not.

Motor Cars.

In Paris, motor cars are much more in evidence than in this country. There are very few in London compared with the French capital. Dr Proust has reported four cases of lead poisoning in Paris, in women aged eighteen, nineteen, twenty-five, and thirty-nine years respectively, whose work consisted in coating with oxide of lead small leaden rods, and fixing them in position. All of these women entered the electrical department of motor car manufactories in good health. At the end of six weeks to two months they had colic, loss of appetite, constipation, and abdominal pain of such severity that they had to be taken to the hospital, and detained there under treatment for more than a fortnight. In one patient the symptoms of plumbism returned shortly after resuming work. With the dangerous nature of the occupation the employers were quite familiar. They not only paid a doctor to visit the works once a week to examine the workers, but they were in the habit of giving to the female workers honey and sulphur, iron pills, and half a litre of milk daily. Ample provision was made for washing; tooth-brushes were provided, also sulphur baths once a fortnight, and yet, notwithstanding these precautions, four of the women quickly developed symptoms of lead poisoning.

Electric Tramways.

An accident of rather a peculiar character occurred on 8th Oct. 1901, on a tramway car in Paris. I state the facts for what they are worth. During the course of the evening, nearly a dozen of the travellers were suddenly seized with violent pains in the abdomen and by syncope, and were obliged to be treated at a chemist’s shop en route. On an inquiry being instituted, the opinion was expressed that the symptoms were due to poisoning caused by fumes given off by sulphuric acid acting upon the lead in the electric accumulators.

Recommendations.

It is evident that as electricity will be the motor power of the future and will be turned into numerous channels of application, the number of electric accumulator works in Britain is sure to increase. The necessity for putting into force several of the recommendations mentioned in these pages is almost sure to arise. So far as the hygiene of the works is concerned, the same rules ought to apply to them as are now in force in red lead works.

Soldering.

Common solder is an alloy of tin and lead, equal parts. Fine solder is composed of 2 parts of tin and 1 of lead; coarse solder, of 2 of lead and 1 of tin. The extensive consumption of tinned meats and fruits is responsible for some cases of plumbism, owing to the acid juices dissolving some of the lead out of the solder, but workmen who solder, e.g. tinkers, have been known to suffer from paralysis of the muscles of the fingers and hands, owing to volatilisation of the lead and inhalation of the fume.

Typefounding; Printing; Typesetting; Linotyping.

Type metal is an alloy of lead with ⅓ to ¼ of antimony. The antimony is added to harden the alloy, for lead is a soft metal. Occasionally small quantities of tin and copper are added, so that the alloy may be composed of 70 parts of lead, 18 of antimony, 10 of tin, and 2 of copper.

We have already dealt with the smelting of lead ore and the melting of pig-lead. The smelting of antimony ore is not attended with such serious risks to health as is the case with lead. One of the largest antimony works in this country is on Tyneside. I have had the privilege of visiting the works and of examining the workmen. The raw ore or sulphide comes from Japan. It is smelted with iron filings. No constitutional bad effects were noticeable in the men who smelt the ore. To some extent this freedom from illness may be due to the fact that the men are not closely exposed to the fume, and that, owing to good ventilation, the fumes were quickly got rid of. The only trouble the workmen seemed to experience, and it was more of a complaint than an illness, is that as the work is hot they perspire freely, and the skin in consequence becomes extremely irritable and itchy. An eruption appears on the skin. This at first shows itself as a crop of vesicles, which ultimately become pustular. Formerly more than now it was a medical practice in the treatment of disease to apply an ointment composed of tartrate of antimony to the skin in order to bring out a pustular eruption, which acted as a counter irritant. Knowing this to be the local action of antimony, it is easy to understand, therefore, the development of the skin eruption spoken of as “pox” upon the neck and upper part of the abdomen in antimony workers. Eulenburg says that exposure to the fumes of oxide of antimony is followed by pains in the region of the bladder and urethra, and by impotence in the male. My experience does not confirm this statement. Several of the men looked rather pale, probably as the result of exposure to the heat, and a few of them had suffered from gastro-intestinal pains like colic, usually relieved by taking a dose of Epsom salts. A case of industrial antimony poisoning is published in the Report of the Chief Inspector of Factories for 1900, p. 332. It is that of a man who had worked as an extractor of the metal, and who in consequence of having inhaled the fumes suffered from paroxysmal attacks of difficulty of breathing without any physical signs of disease in his lungs. He complained of a sense of constriction in his chest, nausea, a metallic taste in his mouth, backache, weakness in the muscles of his legs, profuse perspiration, headache, and dimness of vision.

It is, however, not so much with antimony as with the presence of lead in the printers’ type that we are here concerned. Printers’ colic was a much more common malady two or three decades ago than now. It is due to handling the type, and to the dust that is given off. Typefounders also suffer from plumbism, but in not a few cases the illness has been caused by the workpeople eating their food without previously washing their hands. Printers as a class are often pale and unhealthy looking. Much of this may be due to the fact that they work in overheated rooms for long spells at a time, and have late hours. H.M. Medical Inspector of Factories reports that during 1900 there were 17 cases of lead poisoning in printers. One of the patients died. Ten of the men were compositors, 4 were linotypists, and 2 stereotypers. Dr Stühler, of Berlin, taking his statistics from the reports of sick benefit societies, states that of 3000 printers in Berlin 313 were annually sick from lead colic, i.e., about 10.4 per cent. of printers’ compositors suffer from plumbism, either by absorption through the skin, caused by handling the type that has become oxidised during wear, or by swallowing the dust through eating with unwashed hands. Fromm discusses this subject, and alludes to the analyses of dust of printing-houses made by Stumpf, who found that it contained often as much as 14.43 per cent. of lead. In a report recently presented to the German Board of Health, Faber states that he found in the dust collected from the floor 11.51 per cent. of lead: that the dust taken from a shelf in the room contained 6.59 per cent. of lead, while dust collected in the gangway between the desks in the composing room of a newspaper office contained 4.7 per cent. of lead. In analysing the air of printing shops Keygi[64] found that the dust contained from 10 to 15 per cent. of lead, which came from the wear of the type. Inhalation of the dust of the oxidised metal in all probability, therefore, plays a very important part in the causation of plumbism in printers’ compositors. During 1900, printing was in Britain responsible for 17 cases of lead poisoning. In 2 of the cases there were symptoms of lead encephalopathy, one of which proved fatal, and in another there was paralysis. Ten of the patients were compositors and 4 were linotypists.

It has to be borne in mind that compositors do a great deal of their work in an artificial light. As they are obliged to handle type very freely, the skin on the inner aspect of the last phalanx of the right thumb, forefinger, and midfinger occasionally becomes thick and hard, also the skin of the last phalanx of the left thumb, and the interdigital eminences of the left hand. According to Choquet, typographers suffer from two distinct maladies, one directly due to the mechanical nature of their work, and the other attributable to the medium in which that work is carried on. Standing on their feet for long spells at a time, they run the risk of developing varicose veins, and as the rooms are either too brilliantly lighted, or the reverse, to affections of eyesight. Older compositors frequently show a trembling of the right hand, due to fatigue caused by grasping and distributing the type, but in producing this tremor plumbism no doubt plays a part. Analogous to writers’ palsy, the tremor is sometimes so persistent that it obliges the individual to renounce his work. The channels by which lead dust effects an entrance into the system are the buccal and nasal mucous membranes, the skin, the respiratory passages, and the alimentary canal. So slight are the initial troubles of the typographer, that for a time they are unperceived. Acute plumbism does not occur among compositors, it is always chronic. By degrees the individual begins to look pale; the skin becomes greyish and exhibits a slightly jaundiced tint; the appetite, too, fails, and digestion becomes weak, and obstinate constipation occurs. A blue line, if sought for, will be seen in the gums, and there is complaint of an unpleasant metallic taste in the mouth. The breath becomes fetid, and motor and sensory troubles develop, especially at those parts that have been brought into the closest contact with the type. Often commencing with a sense of fatigue in the muscles, the paresis proceeds to motor paralysis. In female typographers excessive menstrual losses, such as are known to occur in female white lead workers, have been noted.

Whatever tends to interfere with the elimination of lead from the system encourages necessarily the development of plumbism. Alcohol has this tendency. It is said that if the skin of a compositor gets broken, the wound heals slowly and is apt to become erysipelatous, but I have not observed this. Some typographers are more susceptible to plumbism than others. It is largely a question of well or ill ventilated workrooms, and of personal resistance. Tanquerel found in France that the ages between thirty and forty years gave the largest amount of ill health, and that in the hot seasons of the year most cases occurred. Dr Motais, who is a member of the Departmental Council of Hygiene of Paris, in an address recently delivered at a conference of typographers, recited a story of animal life which had been told to him by some of the printers themselves. For twenty years these men had tried to keep cats in the workrooms. The animals were well fed; they received plenty of milk. For a time all would go well with them, and then the same train of symptoms would invariably develop; the eyes would lose their healthy lustre, the limbs become paralysed, and the animals die, presenting the same cerebral symptoms as are observed in the acute lead encephalopathy of man.

Precautions.—Printing houses should be so situated that free currents of air can get to them, and not, as at present is too frequently the case, shut in by other buildings. Plenty of daylight and, if possible, sunlight are very desirable; daylight if introduced by one side should enter preferably on the left of the compositor, so that no shadow is thrown upon the case that contains his type. Light coming in from the roof obviates all this. So far as artificial lighting of the rooms is concerned, there is an opinion that the electric light is more hurtful than gas, and gas again more harmful than lamps. There should be tinted shades on the gas or lamps, green externally, white internally. The workroom should be well ventilated and without draughts; any dust generated should as far as possible be removed by fans. The type boxes should be kept clean and the floors periodically watered. By young compositors long hours ought to be avoided. No food should be eaten in the workrooms. Compositors should never do any work fasting, and should avoid smoking when at work. Excesses of all kinds ought to be avoided, particularly the immoderate use of alcohol. Milk should be freely taken. On the occurrence of colic, the individual should at once give up his work and be medically treated. Washing the hands and rinsing the mouth before eating are absolutely required, also a bath once a week, and the wearing of overalls when at work.

It is an old opinion attributed to the French physicians Tanquerel and Pidoux, that there exists an antagonism between plumbism and pulmonary tuberculosis. Facts so far as applied to compositors do not support this statement, hence the desirability of printing houses receiving plenty of sunlight, and of the undesirability of persons who are bronchitic or susceptible to lung diseases being allowed to work in printing houses, unless they are careful of how they dispose of their expectoration. One of the great foes of the printer is pulmonary phthisis. Much of this is undoubtedly preventible, since the disease is encouraged by the unhealthy conditions under which the work is carried on. Smith[65] found that the mortality from consumption was 60 per cent. greater than in most of the other trades. Of 799 deaths published by the London Society of Compositors for ten years, 1880–1889 inclusive, Arlidge found phthisis as the cause of death in 296, bronchitis and asthma in 85, pneumonia and pleurisy together were responsible for 67 deaths, paralysis and apoplexy for 61, and Bright’s disease for 21. Pulmonary phthisis caused 37 per cent. of the deaths. The largest number of deaths occurred between the ages of thirty and forty years. Since the statistics given by Dr Arlidge are more than ten years old, and as tabulated are not comparable with the general death-rate all over the country of persons between twenty to sixty-five years of age, I communicated with the Secretaries of the Typographical Association, also the London Society of Compositors, for their annual reports, from which I am able through the kind assistance of Dr Henry Armstrong, the Medical Officer of Health for Newcastle-on-Tyne, and his clerk, Mr Gillinder, to supply more recent information, as indicated in the following table (pp. 329–330).

These statistics unfortunately are not exactly comparable: the time periods are not the same for all three. This is unavoidable, owing to the census returns for later periods not having been published while I write. They are, however, not without value, for they strengthen the suspicion of greater liability of the printer to pulmonary disease.

The figures underlined in column 12 indicate the increased tuberculosis mortality rate of the two associations as compared with the whole of England and Wales. In column 11 it will be observed that in the Society of Compositors there is an increase in tubercular disease, but not great, over the corresponding rate for the entire country. It may be therefore taken as a fact that printers are more liable to tubercular consumption than men engaged in most other trades. In the half-yearly Report of the Typographical Association ending December 1900, there is a list of 74 deaths for the half-year in the Society, whose members number 16,179. Of these 74 deaths, 32 were caused by pulmonary disease, and of these 32 deaths, 22 were caused by tubercular disease, mostly pulmonary phthisis. There is an opinion, but it is erroneous, that smoking tobacco or chewing it is more or less a protection against plumbism, because the men expectorate; but apart from the fact of spitting being a dirty practice, the habit of expectorating upon a printer’s floor is to be discouraged, especially if the workman has a cough and is the subject of lung disease, for it is largely by means of the sputa thrown upon the floor and becoming dried that the bacilli of tubercle disseminate pulmonary consumption.

MORTALITY TABLES OF TYPOGRAPHICAL ASS0C.

TYPOGRAPHICAL ASSOCIATION.

No. of Members. Deaths from Total Deaths from Death-rate per 1000 Members.

All Causes. Bronchitis. Pneumonia. Phthisis. Consumption. Tuberculosis, etc. Lung Diseases, including Bronchitis, Pneumonia, Phthisis, etc. Tuberculosis, including Phthisis, and all other forms. Per col. 9. Per col. 10.

1894. 1 2 3 4 5 6 7 8 9 10 11 12

Half-year ended June 30 12,417 61 7 2 21 ... 2 30 23 ... ...

„ „ Dec. 29 12,544 46 2 2 11 ... 1 15 12 ... ...

Whole year 12,480 (average) 107 9 4 32 ... 3 45 35 3.6 2.8

1895.

Half-year ended June 29 13,378 78 6 9 23 ... 6 38 29 ... ...

„ „ Dec. 28 13,593 65 6 5 16 ... 3 27 19 ... ...

Whole year 13,485 (average) 143 12 14 39 ... 9 65 48 4.8 3.6

1896.

Half-year ended June 27 13,673 75 5 7 17 ... 2 29 19 ... ...

„ „ Dec. 26 13,906 68 2 8 26 ... 1 36 27 ... ...

Whole year 13,784 (average) 143 7 15 43 ... 3 65 46 4.7 3.3

1897.

Half-year ended June 26 13,862 82 6 8 19 ... 4 33 23 ... ...

„ „ Dec. 25 14,405 54 4 2 21 ... 1 27 22 ... ...

Whole year 14,133 (average) 136 10 10 40 ... 5 60 45 4.2 3.2

1898.

Half-year ended June 25 14,602 77 5 3 22 ... 2 30 24 ... ...

„ „ Dec. 31 15,075 69 5 1 19 ... 1 25 20 ... ...

Whole year 14,838 (average) 146 10 4 41 ... 3 55 44 3.7 3.0

1899.

Half-year ended June 24 15,393 78 7 6 23 ... 3 36 26 ... ...

„ „ Dec. 30 15,854 99 2 13 39 ... 4 54 43 ... ...

Whole year 15,623 (average) 177 9 19 62 ... 7 90 69 5.8 4.4

Average for 6 years 4.5 3.4

LONDON SOCIETY OF COMPOSITORS.

Year 1897 10,780 126 13 10 33 ... 11 56 44 5.2 4.0

„ 1898 11,079 141 10 5 40 1 11 56 51 5.0 4.6

„ 1899 11,415 132 11 9 28 1 7 49 35 4.3 3.0

Average for 3 years 4.8 3.9

England and Wales.—Per 1000 Population (1881–90).

Mean Annual Death-rate of male persons, 20–65 years of age 4.5 1.8

In thus expounding the subject of lead poisoning in printers, I have rather drawn attention to dangers that were more common in the past than exist at present, for, fortunately in this country at least, plumbism among compositors is very much on the wane. It is seldom that we meet with cases of printer’s colic in these days, owing very largely to the change in the method of printing newspapers. Until recently the printing of newspapers was done by ordinary type, the compositor setting the type by touch and not by sight. He quickly picked out the required letters, deftly inserting the nail of his thumb into the groove on one side of the type. It was through these operations that the skin of the fingers became thickened, and lead dust got under his finger nails. Having set and printed the paper, he had to take up, wash the type in lye, and subsequently distribute it, i.e., put each type back into its proper place. The distribution of the type required even more care than the setting of it, for a type wrongly distributed became a source of future trouble. Printing by hand type is rapidly on the decline, and is being replaced by stereotyping and linotyping. For newspaper printing there are now several fast printing machines in existence. Stereotyping has made it possible to print from a stamped cylinder without making direct use of the individual type. Endless rolls of paper, too, feed the printing machines. As many as 10,000 thirty-two page periodicals can be thrown off in an hour, but by perfecting the apparatus, as in Hoe’s machine, as many as 24,000 are capable of being thrown off in an hour. It is in typesetting machines with automatic distribution that the greatest progress has been made. The Merganthaler linotype machine, which is used for newspaper printing, produces and gathers in order successive bars of metal, each of the required length and breadth of a line, and bearing on its upper surface the type which prints the line. In the machine are small brass matrices, representing the different letters, etc. When the operator presses a finger-key on the board in front of him a single matrix bearing the required letter falls out of the magazine, and is carried to the assembling block, where the various matrices are set up, side by side, in a line or row. Subsequently these are transported to the face of a vertical mould wheel. Into the face of the mould molten type-metal is pumped, and thus a slug or linotype is produced. As the formation of the slugs is effected automatically, the operator does not handle the metal, consequently plumbism is rare, only two cases of lead poisoning in linotypists appearing in the Annual Report of the Chief Inspector of Factories for 1899, and four in 1900.

The new methods of printing have certainly diminished the numbers of cases of lead poisoning among printers, but the introduction of linotyping is losing us, as a people, an art. No person contends that, for finish, linotyped printing is equal to that obtained by hand-set type. Except for book-printing, in which the letters stand out boldly and clearly, and which as a trade is being relegated to a few towns, stereotyping and linotyping are in our own country rapidly eliminating typography. Since this is unavoidable, it is to be hoped that linotyping will yet further improve, for badly-printed newspapers are trying to the eyes. On the Continent most of the small newspapers are still printed by hand-set type, and consequently lead poisoning among printers is more prevalent there than here.

Compositors working the linotype machine run little risk of lead poisoning if they keep themselves and the workrooms clean. In linotypists the danger is not in handling the metal, for the need of doing this is rare; it is rather through inhalation of the fumes of the molten lead or from oxidation of lead particles that are lying about on the machine and floor. I have met with a few cases of colic in linotypists, but the attacks of pain have been mild and much more quickly got over than in compositors who use the ordinary type. In some, too, I have observed some of the milder derangements of the nervous system, mostly functional, that are the result of plumbism.

Plumbing.

Plumbers are not a long-lived class. They suffer from lead poisoning in consequence of handling sheet-lead, pipes made from the same metal, also from working with white lead. They often complain of a sweet metallic taste in the mouth during the beating of the lead and the application of solder.

Gasfitters and plumbers run the risk of being poisoned also in another manner, to which allusion may be incidentally made here. When making the necessary connections between the pipes going into the houses and the mains, the gas in the latter is not shut off on account of its requirement by consumers. As a consequence of exposure to coal gas escaping from the main pipes, the workmen occasionally become dizzy and unconscious, lose their eyesight for several minutes, as well as the muscular power of their limbs. They have to be removed by their fellow-workmen, who often administer an emetic of salt and water when consciousness has sufficiently returned to enable them to swallow. The vomited matter smells strongly of coal gas. The symptoms are known as “gassing” by the workmen. In some of the men who have thus suffered I have found that complete muscular power had not returned to the limbs three months after the accident, that the knee-jerks were exaggerated, and that the patients were nervous and the subject of tremor. Albumen or sugar may be temporarily present in the urine.

House Painting.

House painting is a prolific cause of plumbism. Dr Stühler, of Berlin, who obtained his facts from benefit societies, states that of 3000 painters in Berlin 313 or 10.4 per cent. were annually off work from the effects of lead poisoning. In Paris, Gautier found that out of 14,000 painters and varnishers 250 on an average attended the hospitals on account of plumbism, and that an equal number was treated at home, making a total percentage of 3.5. Of late the admissions into the hospitals of cases of lead poisoning have been increasing notwithstanding the regulations issued by the French Government, and the fact that the patients coming from white lead works have been getting fewer. This circumstance is explained by other industries sending more patients than formerly, and of these industries house painting has contributed the largest number. During the years 1894–98 this trade alone, and colour-grinding, contributed 223 patients, while white lead works only sent 4, and the occupation of plumbing 22. Of 86 fatal cases of lead poisoning in Paris during the five years mentioned, 43 occurred in painters, 2 in plumbers, and only 1 in a white lead worker. In consequence of the large amount of plumbism that prevails among house painters in Paris, it is Gautier’s contention that the occupation should be brought under closer Government supervision. The same remark applies equally to the trade in our own country. Lead poisoning among house painters is much more prevalent than people imagine. Taking a few monthly reports at random, there were 12 cases of plumbism in house painters (with 1 death) reported to the Home Office during the month of June 1900; in the month of November 1900 there were reported 11 cases of lead poisoning (including 2 deaths) among house painters and plumbers, and in the following month 14 cases of lead poisoning (including 4 deaths) in house painters and plumbers. During 1900 there were 199 cases of lead poisoning in house painters and plumbers reported to the Home Office. These figures show that if Saturnine poisoning in house painting was notifiable, both it and plumbing would be found to be trades that are the cause of a great amount of sickness, of which at the present time we hear very little. During the year 1899 upwards of 100 cases of lead poisoning were notified, while from district registrars information was received of 18 fatal cases of plumbism attributed to the occupation of house painting. Notification of lead poisoning in house painters is not compulsorily required by the Home Office. Cases of industrial lead poisoning, also arsenic, phosphorus, mercury, and cases of anthrax, are obliged to be reported to the Chief Inspector of Factories by the medical men who attend the patients, and by employers, but an exception is made in regard to house painting, one of the reasons being that as painters pursue their avocation largely in the open air and in houses away from the employer’s premises, it is difficult to say where the poisoning was contracted. Industrial lead poisoning to be notifiable to the Home Office must have occurred in places that are controlled by the Factory and Workshop Acts. When a painter, who is following his occupation in a factory or workshop and is engaged in grinding or mixing colours, develops lead poisoning, the illness has to be notified. As the Act stands at present, the Home Office cannot deal with certain forms of industrial lead poisoning, nor have the factory inspectors power to enforce improved conditions of labour. In view of house painting being ultimately brought under Special Rules, it is very desirable that all cases of sickness in house painters and deaths from plumbism should be reported. To the ordinary medical practitioner, who has been informed that he must report all cases of occupational lead poisoning coming under his care, it is embarrassing for him to draw a distinction between lead poisoning caught by one man filling a barrel with dry lead carbonate in a workroom, and another man who uses this as a paint in decorating the interior of a house or shop, and yet while the former is notifiable, the latter is not, although the same cause is in operation in both. The sphere of Home Office influence ought therefore to be extended so as to include house painting, and this might be done under the Act that allows the Home Secretary on sufficient evidence to schedule a trade as dangerous.

There are several ways in which painters and colour-mixers become the victims of lead poisoning. The men who grind or mix the colours run the risk of inhaling the dust. Unless this process is carried on either in closed spaces or in airy and well-ventilated rooms, the atmosphere becomes thick and can only be cleared by means of a fan. In this country there are, excluding house painters, upwards of 6000 persons employed in the manufacture, mixing, and grinding of paints and colours. Of 48 cases of plumbism that occurred among these persons in 1899, 30 were grinders and 7 of them packers.

For the purposes of house painting, the pigments are generally mixed with oil and a turpentine body. It has sometimes been thought that the lead poisoning of painters is due to the inhalation of the terebinthated vapour that rises from the painted surface. That this is a possible source is shown by the outbreaks of “belly ache,” or colique sèche, that occurred a few years ago in the Tropics, and played sad havoc with the sailors of the French Navy. For a long period the nature of the illness was not recognised. It was thought by some to be a neurosis of the abdominal sympathetic nervous system, and due to chill, while other physicians regarded it as a form of malarial disease. Lefèvre, the Director of the Naval Sanitary Board at Brest, ultimately gave it as his opinion that “the colique sèche of the French Navy is nothing more than lead poisoning, and the reason why colic was more frequent among French sailors than those of other countries was due to the fact that lead entered more into the construction of their ships of war. It formed the tanks for holding the drinking water and the pipes for carrying the water; it was present in the paint of the cabins, in the enamel of the drinking-cups, and in the cooking utensils.” Out of this number of possible causes some of the cases of colique sèche might have been due to sleeping in cabins newly painted with lead compounds, although drinking contaminated water would be the more probable cause. A common cause of lead poisoning in house painters is inhalation of the fume evolved during the burning-off of old paint. When engaged for long at this kind of work the men complain of headache, nausea, and occasionally have colicky pains in the abdomen. There is yet another manner in which plumbism may develop, and this occurs in finer work, where several coats of paint have to be applied. After what is called laying-on of the prime colours and puttying with white lead comes the flat colouring. When the coats of paint have become dry the workman is obliged to use sandpaper to rub the surface flat. In doing this a considerable amount of dust is given off which is rich in white lead. It is inhalation of this dust that so frequently induces colic and paralysis of the hands in house painters. Carelessness and ignorance are frequently contributing causes. Men, while laying-on the white paint with a flat knife, have often been observed using the hollow of their left hand as a reservoir for the paint. If there is any erosion of the skin, absorption of the poison is sure to follow. Layers-on are an unhealthy class of men. In Paris alone there occurred 18 deaths during the years 1898 and 1899 in a small union of 200 members, the greatest age at death being 35 years.

A fresh danger has been recently introduced into house painting. A few months ago a house painter, aged 40, was admitted into the Newcastle Infirmary suffering from extreme blueness of the face, lips, ears, hands and fingers, and from colic. He had also a very blue line on his gums. The illness was plumbism, but with something superadded. He had been engaged in removing the varnish and paint from old Venetian blinds, and had been using a dark brown liquid with a pungent, penetrating odour, known in the trade as a special patent. During the process of rubbing and swilling the blinds, and subsequently of sandpapering them, a strong sickening odour arose, which caused him to vomit and to have severe headache. The vapour, too, caused him to become so drowsy that he would almost fall asleep. He would feel giddy, but had no difficulty in walking, nor was his eyesight affected. The man was pale as well as blue, he had a haggard expression, and there was the most marked cyanosis possible. He had colic and constipation. His internal organs were healthy, including the kidneys. He had marked tremor of both hands, but no paralysis. It was quite clear that there was an acute intoxication of some kind or another, over and above lead poisoning. Several examinations of the urine were made by Dr R. A. Bolam, who had charge of the patient, with the view of establishing the nature of the poison. The symptoms reminded me of those observed in men who are employed in painting ships with quickly-drying spirit paints. It was thought at first that the symptoms were due to the presence of aniline oil in the “patent,” or of some chemical akin to the pyridine group of compounds. The case is an illustration of the danger incidental to the use of highly volatile, complex, and unstable chemical compounds whose nature is not quite known, whose effects upon the human body can only be learnt by experience, and which have for their object, from a trade point of view, rapid execution of work.

Painters of ships’ cabins suffer from plumbism as much if not more than house painters, since they are often obliged to work in close, confined spaces; so, too, do the painters of the back of mirrors, from using red lead; also painters of agricultural implements, etc.

It is worthy of mention that shipbuilders have found in the red oxide of iron a cheaper and safer pigment for painting the outside of steel plates than red lead.

The question as to whether any comparatively harmless substitute for white lead can be found for house painting is discussed at p. 293, q.v.

Coach Painting.

Lead poisoning in coach and carriage painters is far from being rare. In the painting of carriages there are often as many as eighteen coats of paint and varnish applied. Frequently the work is done in rather close and very ordinarily ventilated places. In Newcastle it is the practice of large firms of coach makers to give a carriage three coats of primary paint, six of filling up, three or four of oil colours, two of varnish colour, i.e. oil and varnish mixed, and, finally, about four coats of varnish. The colours used are white lead, dry and ground in oil: lampblack, ultramarine, yellow chromes, zinc white, and others known by particular names in the trade. “Driers” are also used, such as sugar of lead and terebene. Coach painters become the subjects of plumbism chiefly through inhaling the dust when sandpapering to get a good surface. They suffer from colic and wrist-drop. Many of the cases approach in severity the lead poisoning of file cutters. Dr Morison Legge states that the percentage of chronic plumbism among coach painters is greater than among file cutters.

Several cases of plumbism have occurred in the painting of new carriages, also in the breaking-up and burning of the wood of old railway carriages. Thirty-four of the cases of plumbism reported during 1900 as having taken place in coachbuilders. occurred in men engaged in railway shops.

It is almost unnecessary to repeat that in all places where lead paints are being handled and used, as in workshops, factories, ships and dockyards, there should be adequate washing accommodation, with plenty of soap, towels, and nail-brushes, and sufficient time ought to be given to the men to wash before leaving work.

Glass Polishing.

After glass and crystal have been cut they have to be polished. The polishing is generally conducted on a revolving wheel or table made of wood, and upon which water, containing rouge or putty powder in suspension, is allowed to drip. When the article to be polished is a plane surface, e.g. a mirror, the wheel is a horizontal one revolving on a vertical axis. The water containing the rouge or putty powder escapes by a narrow opening from a conical vessel placed above the wheel. When finer work is required, e.g. the polishing of wine-glasses, electric-light globes, etc., the water drops on to a hard brush, which is attached to the external rim of a vertical wheel, from four to six inches in diameter, running at a high speed and revolving on a horizontal axis. For this kind of polishing putty powder alone is used. In some factories the liquid putty powder is fed on to the brush by a boy; in others the supply, as already mentioned, is automatic. Several samples of putty powder were sent to the Dangerous Trades Committee, and subjoined is the analysis of two of them:—

A. B.

Oxide of tin 29.72 per cent. 28.96

Oxide of lead 70.28 „ 68.07

In the very free use of this putty powder, rich in lead, the clothes and hands of the workers become bespattered by the thick spray thrown off from the rapidly-revolving wheels. Putty powder administered to animals in their food causes symptoms of Saturnine poisoning almost as quickly as white lead. In the evidence given before the Dangerous Trades Committee there was abundant proof of the extremely harmful effects of the use of putty powder in glass polishing. Many of the workers examined had suffered from colic, while others had been obliged to give up their employment on account of paralysis of the fingers and hands. It was ascertained that several of the male workers had died from acute convulsive seizures due to poisoning by lead. Another point to which attention was drawn was, that plumbism might develop in workmen in a glass-polishing shop who were not engaged in the actual process of polishing, and who had therefore not been directly brought into contact with the putty powder. This was due to the dried liquid on the floor becoming rubbed and trodden upon, rising as dust into the atmosphere, and being inhaled by the workmen in the shop.

Putty powder is a frequent cause of lead poisoning. The master polishers have for years tried to find a substitute for it. In many factories rouge is used. This is considered by many of the employers to be innocuous. On analysing rouge powders for the Dangerous Trades Committee, Professor Thorpe found that they contained commercial oxide of tin: that in one powder 0.13 per cent. of arsenious acid was present, and in another a trace of the same substance. Probably not much danger would follow the use of rouge powders containing such a mere trace of arsenic, but their employment would not be altogether free from risk; besides, since it can be shown that the presence of arsenic is not essential, then it ought to be eliminated altogether. The difficulty in regard to the use of harmless rouge powders is rather a technical or industrial question than medical. Do they answer the purpose as well as putty powder? The Dangerous Trades Committee found that opinions were much divided upon the point. Some of the glass polishers stated that rouge did not give such a fine effect, and that it took a longer time. On the whole, however, the results obtained have been such as to encourage employers to adopt it more freely. Where putty powder has been interdicted by the masters and only rouge used, the health of the workmen has wonderfully improved.

A few years ago M. Geroult proposed to the French glass polishers and crystal manufacturers, metastannic acid as a partial substitute for the putty powders that contained a large percentage of lead, and which had been the cause of several fatal cases of plumbism. The Academy awarded the Montyon prize to Geroult for his discovery. For the last ten years the new method has been followed in the glass works of Baccarat, and has given the most satisfactory results. Dr Schmitt, the surgeon to the works, says, that since 1891, the date of the substitution of the new for the old method, there has not been one single case of lead poisoning among the crystal cutters and glass polishers, nor an acute attack of plumbism in those workers who had previously suffered from lead poisoning. Formerly the putty powder contained 62 per cent. of lead, but in that recommended by Geroult there is only 20 per cent., and even with a smaller percentage of lead good manufacturing results can be obtained.

Glass polishing is one of those trades in which personal cleanliness of the worker can do a very great deal to prevent plumbism, and, knowing this, employers ought to provide ample washing accommodation and appliances; overalls should be worn; no food should be taken into or eaten in the workshop. All polishing should be conducted as far as possible in semi-enclosed cupboards, with draught tubes and fans, and the feeding of the wheels should be done automatically. There ought also to be frequent periodical medical examination of the workers, with power to suspend in case of signs of plumbism. These were the recommendations of the Dangerous Trades Committee, and as one result of their being put into practice the Medical Inspector of Factories, in his Report for 1899, says he is satisfied that the introduction of fans has materially diminished the danger of lead poisoning in the process of glass polishing. It has, practically speaking, abolished the bespattering of the workmen’s clothes and the splashing formerly observed during glass polishing.

File Cutting.

Hand file cutting, although still giving employment in this country to a fairly large number of people, is generally stated to be a decaying industry. This is controverted by Dr John Robertson, Medical Officer of Health, Sheffield. It is, however, an unhealthy trade. In 1898 there were 46 cases of lead poisoning reported in file cutters, in 1899 the number was 41, and in 1900 there were 40 cases. The centre of the industry is Sheffield, but the manufacture is carried on in London, Glasgow, Rainhill, and Birmingham. There are upwards of 2000 hand file cutters in Sheffield alone. In the Annual Report on the health of the City of Sheffield, 1900, it is stated that there are 2040 persons engaged in 546 hand file cutting shops. Files can be cut both by hand and by machinery, but as file cutting by machinery is usually carried on in modern and well-ventilated factories, this method of manufacture need not detain us, for it is a healthy occupation, there being no lead used in the process. It is otherwise with hand file cutting. Seated on a “stock,” the hand file cutter has in front of him a stone block, into the centre of which a small piece of bar steel called a “stiddy” is inserted, and on this stiddy is placed a piece of metallic lead, which is called the “bed.” The file about to be cut is strapped on to the bed. The lines that are seen on a file are made by means of a chisel and hammer, each line representing a blow. The reason for using the lead bed to strike the file upon is, that while there may be as little recoil as possible, there shall yet be sufficient resistance to develop the line in its entirety as a result of the blow given by the hammer and chisel. As a consequence of constantly striking files of uniform size a groove comes to be formed on the lead bed, into which succeeding files easily fit. When he has cut one face of the file, the workman rubs that side with charcoal, turns it over, and then proceeds to cut the other side, after which both faces are briskly rubbed. The file cutter grips the chisel between the index finger and thumb of the left hand, and in order to get a good grip of the chisel, he often licks his finger. A good deal of strain is experienced by the fingers in a day’s work. The steel hammer used by a cutter generally weighs from 7½ to 9 lbs., and as each line on a file represents one stroke of the hammer, and there are often on large files as many as 3800 lines, it is estimated that in the course of one day a file cutter will lift a weight equal to several tons. A Gateshead file cutter, who consulted me recently, works with a hammer 7 lbs. in weight; he cuts files 16 inches in length. Each file receives 1500 “bats,” and he makes one and a quarter dozen of files daily, working eight to eight and a half hours. In the course of a day’s work he lifts 157,500 lbs. weight.

File cutting by hand is properly regarded as a dangerous industry. Although it claims annually large numbers as the victims of plumbism, it is difficult to say exactly in what form lead enters the system. In Sheffield the work is for the most part carried on in small, badly-ventilated, and overcrowded shops, more like outhouses, often situated in backyards or in the rear of dwellings, and not unfrequently contiguous to privies. Of 546 hand file cutting shops, in only 48 was there any means of ventilation provided, and in many of these “the means of ventilation consisted of a brick taken out of the wall.” Inside, the floor in nearly all of them is the bare earth, or bricks badly placed together. The workers are closely packed together without any consideration of the cubic space of the workroom. Hand file cutters as a class are anything but cleanly. Possibly their sense of indifference to dirt is largely the outcome of the long custom of the men taking their meals in shops totally unprovided with washing appliances. As a consequence of hammering and brushing the files, a considerable amount of dust is created, some of which must be inhaled, as the man or woman—for both sexes follow the occupation—bends closely over the stock. In several samples of dust removed from the stocks and rafters of the shops, lead[66] was found, the other constituents of the dust being particles of iron, charcoal, and chalk. File cutting is a sedentary occupation. In order to get as much light as possible upon their work, the men sit close up to the window, but they object to any part of the window being open on account of the cold and draughts. Owing to the close and dusty atmosphere in which the work is carried on, the general health of the file cutter becomes gradually undermined. As a consequence of this diminished vital resistance, and the practice of eating his food with unwashed hands, the licking of his fingers when at work, and inhalation of dust, the file cutter, in course of time, becomes the victim of lead poisoning. It is metallic lead dust that is given off during the blows with the hammer and chisel upon the file. Lead in this form is certainly much less harmful than when in such a soluble combination as the oxide or carbonate, but oxidation of the surface of the lead is constantly taking place, thereby rendering the metal more or less absorbable.

In addition to the ill-health caused by lead, pulmonary consumption carries off a large number of file cutters. The men work in a stooping position in overcrowded and ill-ventilated shops for long hours daily, with the result that the trade occupies an unenviable position on account of its mortality from phthisis. It is not, therefore, lead quâ lead that is the sole danger, but the unhealthy conditions under which the labour is carried on.

In Sheffield, file cutting has received considerable attention from members of the medical profession. Thirty years ago Dr J. C. Hall denounced the trade as unhealthy, and demonstrated how, with such simple means as the free use of soap and water, much of the suffering and ill-health traceable to lead could be averted. Drs Sinclair White, Porter, and Harvey Littlejohn have in recent times written upon the evils of the trade from different standpoints. Notwithstanding all the attention the subject has received, hand file cutting still remains a most unhealthy industry. All the workers look anæmic. Many whom I examined both in Sheffield and in Rainhill had suffered from colic; several were completely disabled on account of paralysis of the extensor muscles of the fingers and wrists. It is rather in the chronic forms of plumbism, and in those persons in whom the kidneys become affected and health breaks down, that the worst effects of file cutting as an occupation are seen. Out of 100 file cutters examined by Dr Sinclair White, 74 had a blue line on the gums, 28 had had lead colic, and 20 paralysis of the wrists and fingers. The trade is characterised by a high mortality, the figures being 316 against 123 for occupied males in general.

The possibility of finding a substitute for the lead bed upon which the file is cut is, although not a new subject, one to which the Dangerous Trades Committee gave considerable attention. It was felt that if lead could be eliminated, the occupation would be rendered much less harmful. It was ascertained that in Germany pads of paper had been tried for small files, also that clay and sand encased in canvas, bars of wood, copper, vulcanite, and various combinations of indiarubber and gutta-percha had been tried, but each in turn discarded, owing to its unsuitability as a bed. This is a field of inquiry that would well repay any practical file cutter.

File cutters may work at their trade for years without becoming ill. Others again early suffer from colic, and the attacks of abdominal pain keep recurring every few months. Gradually, or suddenly, in those who have been thus afflicted, or even in those who have not had colic, paralysis of the fingers and hands develops. The peculiarity of file makers’ paralysis is, that while the extensor muscles of the fingers and wrists may become affected, so as to constitute a veritable “wrist-drop,” there is observed more frequently paralysis with wasting of the smaller muscles of the fingers and thumb. The loss of power is usually confined to the fingers of the left hand. It is with the left forefinger and thumb that the chisel is grasped, and as a consequence of the workman holding the chisel in this position during a great portion of the day, there is an amount of muscular strain experienced which cannot but play a part in determining the paralysis and its location. It is not the sole explanation, however, for the paralysis also affects at times the muscles of the right hand of the file cutter. This is the hammer hand that really does the hardest work, though not of the same strained character.

While it is to the fact of the work being conducted upon a lead bed, and the want of personal cleanliness on the part of the file cutter, that plumbism is mainly due, there are, as seen in Sheffield, contributory causes in operation which tend to increase the harmfulness of the occupation. One of these is, that file cutting is often a home industry. The work is frequently carried on in the living room or kitchen of a dwelling-house. Domestic and family duties come to be disregarded by the mother, for she, no less than the other members of the family, interruptedly lends a hand to increase the income of the home. Readers of this paper are prepared to learn that work under these circumstances is usually carried on in houses of the poorest description, and that, as a consequence of the dangerous character of the occupation, the unhealthy atmosphere of the workroom, and the constitution of the workers having become undermined through poverty, lead poisoning when it occurs is not only extremely severe, but may affect those who are simply living in the house and not actually engaged in file cutting at all. How to grapple satisfactorily with this most unhealthy trade is one of the many difficult labour problems that have been presented to the Home Office. Both for it and the peculiar tenement conditions under which the industry is carried on in Sheffield, fresh legislation is required.

In file cutting shops generally, the air space ought to be extended to 450 cubic feet at least for each person (it is 600 feet in cotton factories); there should be greater distance between the stocks, say 4 feet; better ventilation; washing appliances, with plenty of soap, water, towels, nail-brushes; wearing of overalls; periodic lime-washing of the workshops; concrete, asphalt, or wooden floors, which can be damped and swept regularly; prohibition of the taking of food into the workshops; and in the event of new buildings being erected, submission of the plans to the Home Office. For ventilation purposes Dr John Robertson recommends an inlet of the type of a Sherringham valve.

The report on the sickness experience of the Society of File Cutters by Hand in Sheffield, by Mr Stuart Uttley, Secretary of the Federated Trades Council, and which is published in the Fourth Interim Report of the Dangerous Trades Committee, 1899, p. 21, shows the extent to which file cutters are thrown off work every year through illness, including lead poisoning. This Society does not contribute any sick benefit, but during the illness of members their contributions to the Society cease. In this way it is readily known how many members are off work. The report deals with adult males only, and the dates chosen are 1891 and 1896, two years when trade was good, when all the members were at work, and malingering was practically beyond question. Out of 1092 members in the Society in 1891, the claims for exemption on account of sickness were equivalent to 1109 weeks, or a fraction of over one week per man per year. It is not maintained that all the sickness was due to plumbism. In 1896, 961 file cutters who were working in Sheffield claimed 951 weeks’ exemption from payment of contributions on account of sickness, or a fraction under one week each per man per year. There were 36 cases of plumbism in file cutters notified in Sheffield from July 1898 to June 1899, and of these 35 were men. A glance at Dr Tatham’s tables of comparative mortality, in an earlier part of this book, will show to what a large extent pulmonary consumption prevails in file cutters.

Dr Harvey Littlejohn found that in twelve years there occurred 91 deaths from plumbism in Sheffield, and that of the 91 people who died, 56 were file cutters. These statistics, however, do not represent the total number of deaths from lead poisoning. Plumbism is sometimes so tardily developed, and the constitution of the workman so gradually undermined, that as pathological changes are very slowly induced in internal organs, such as the kidneys, an individual may die long after he has given up working in lead, and the death be registered as having been caused by chronic disease of the kidneys, which but for lead poisoning would probably not have developed at all. It is thus that many fatal cases of lead poisoning fail to be attributed to their proper cause, owing to the fact that as death is the result of well-defined disease of internal organs, the connection of which with plumbism is overlooked, the occupation of the patient is either not inquired into or is completely ignored by the medical attendant. It was with the view of minimising this error, and of bringing into greater prominence the connection of lead poisoning with industrial occupation, that the Dangerous Trades Committee suggested in its final Report, 1899, p. 6, that if all deaths among workpeople who had been employed at any time within three months immediately preceding death in a trade in which Special Rules are established were compulsorily reported to the coroner, many facts of intrinsic and statistical value would be ascertained, and much light shed upon some of the occupations that give rise to industrial disease. By this means much injury and suffering might be mitigated at an earlier date than at present through alteration of the conditions under which the particular industry is carried on. Possibly six months would be better than the three suggested in the above sentence. Usually lead poisoning is so slowly and insidiously developed in file cutters, that the workpeople become indifferent to the dangers, and yet when symptoms of plumbism occur they can be very severe. Occasionally in female file cutters the malady shows itself at an early date after exposure, and the symptoms are those rather of the acute than the chronic form of plumbism.

Since, doubtless, the tendency to plumbism in file cutters is favoured by the nasty habit indulged in of licking their left thumb in order to get a better grip of the chisel, the application of resin to the finger has been recommended, but the suggestion does not appear to have met with much approval. Allusion has been made at the commencement of this article to the fact that it is only hand made file cutters who suffer from lead poisoning. In the United States all file cutting is done by machinery, and in that country plumbism among file cutters is unknown. In Britain machine-made files are slowly supplanting those cut by hand, but the customs of a trade die hard.

Use of Lead in Potteries.

Staffordshire is the home of the pottery industry in this country. In Stoke-on-Trent, Burslem, Hanley, Longton, Fenton, and Tunstall, the trade is centred. These towns form what is called the “Potteries,” a district of about ten miles in length and four in breadth. Here nine-tenths of the earthenware produced in the United Kingdom are manufactured. The location of the manufacture of pottery in Staffordshire is an illustration of how industries cling to particular districts. At the present time none of the clay which is used in the manufacture of the finer earthenware is found in the neighbourhood. Originally there was plenty of coarse clay, and there is still abundance of marl, which is used for making saggers and firebricks. Coal, however, is abundant, and cheap fuel is an important item in the manufacture of pottery. In the early part of the seventeenth century there was a good supply of clay and fuel in the locality. The ware produced at that time was made from yellow or red marl, glazed with galena, or crushed raw lead ore brought from the Derbyshire mines; but in 1680, common salt was substituted for galena in the glaze. The articles produced were known as Crouch ware. It was in Burslem that this ware was first made. In 1759, Wedgwood perfected the white cream ware, and introduced many improvements into pottery, especially in the manufacture of green, black Egyptian, and jasper wares. Although England never outrivalled France and Germany, e.g. Sèvres or Dresden, in the manufacture of soft china, yet she has produced earthenware on a larger scale and supplied more of the world’s markets than other pottery districts, and is still doing her utmost to maintain her supremacy. In Staffordshire there is plenty of common clay, marl, or fireclay which, as already mentioned, is useful for making saggers, i.e. the large vessels in which earthenware is fired. The clays necessary for making the finer earthenware and china are brought from Dorset, Devon, and Cornwall. The clay or felspar used is, roughly speaking, a silicate of alumina in combination with water, potass, soda, lime, or iron. These ingredients act as fluxes on the silicate, and therefore help its vitrification. For earthenware, two kinds of clay may be used, the blue or ball clay and kaolin, but for porcelain only kaolin. It is estimated that upwards of 70,000 tons of ball clay are annually imported into the Potteries from the south of England. Kaolin, the Chinese word for the clay out of which porcelain is made, is in Staffordshire called China or Cornish clay, and is got from granite rocks. Workmen mix this Cornish clay with water in a large tank. The quartz, mica, and undissolved felspar sink to the bottom, while the thick white water in which the fine particles of kaolin are suspended is run off into another tank in which the kaolin is allowed to become precipitated. The precipitate is subsequently removed, dried, and exported from the south of England as a very fine white clay, which contains more alumina but less iron than the untreated clay. Of this material about 130,000 tons are sent to the Potteries every year. In Staffordshire what is called Cornish stone is also used. This is a kind of granite in which the felspar retains its alkaline elements, and is also useful as a vitrifying agent. Ground flints, too, are employed in the manufacture of earthenware. Ball clay forms the foundation of earthenware; flint is simply the whitening material. The addition of Cornish clay makes the body still whiter and less liable to break under a heavy weight and changes of temperature, while Cornish stone renders the ware more compact and of a closer texture. A mixture of these substances when fired would not produce earthenware of a perfectly white colour. The iron contained in them would impart a yellow tinge. This is overcome by adding oxide of cobalt, which neutralises this tendency so completely that white ware is produced.

It is unnecessary to describe at any length the process of manufacture. Once the ware is made it is gently dried by exposure to the ordinary air; afterwards it is placed in saggers and fired in large cylindrical ovens, slowly at first to prevent too sudden evaporation of moisture and to prevent splitting. When the ware has undergone its first firing it is known in the trade as biscuit. Common terra-cotta and stoneware only require one firing, but for all English ware it is necessary that it should be placed twice in the oven so as to get a denser texture of the ware, also for the purpose of glazing, or that process whereby the article is dipped in a liquid in which usually raw or ground vitrified lead is suspended. If the ware is to remain white, it is, after it has been biscuited, sent to the dipping department to be glazed, and if it is to be decorated and sold as an inexpensive ware it goes in addition to the printing shop, where by means of thin paper transfers it receives the desired coloured impression. The more expensive ware is painted by hand in the ordinary way by means of small brushes. In underglazed colouring the decorated ware is placed in a kiln and brought to a red heat so as to burn off the oil in the colouring. The earliest glaze used in Staffordshire contained galena or sulphide of lead. The materials used for glazes are the same as those for the body, viz., silica as found in flint, and felspar, to which is often added Cornish stone. These are called the hard materials, and they are vitrified by such fluxes as oxide or carbonate of lead, borax or boric acid, potash, soda, carbonate of lime and barytes. In the Potteries each manufacturer has his own receipt for glazes, and he guards it with a conservatism that to outsiders seems unnecessary in these days of advanced chemical research. The ingredients or the glaze can be rendered very insoluble by vitrifying them in a reverbatory furnace or crucible by exposure to an intense heat, whereby a compound like green glass is obtained, which is called a fritt. This is subsequently ground and mixed with water. Into this liquid the ware is dipped, and having been biscuited, the porous ware rapidly absorbs the water, leaving the solid particles of the glaze on the surface. Instead of fritting the lead, many manufacturers until lately simply added raw lead, i.e. white lead or carbonate, to the other ingredients in the dipping tub, and it is owing to persistence in this practice that lead poisoning has been so prevalent in the Potteries. After the ware has been dipped in the glaze it is fired for a second time in a manner similar to the first, only in smaller ovens, and with greater care, the individual pieces being better separated from each other. On removal of the ware from the oven it is ready for the market. In most factories the ware, after having been dipped, is dried and cleaned by women, i.e. the borders are scraped with a knife to remove any surplus glaze. When this process of cleaning is conducted over a trough that is aspirated there is very little dry glaze dust scattered about the room, but if performed in a room without proper ventilation the atmosphere becomes dusty and dangerous. Ware cleaning ought never to be conducted in the same room as the dipping.

What is called porcelain or china differs slightly from earthenware. There are three kinds of porcelain: (1) that made from kaolin and felspar, with the addition of quartz: this is manufactured in Limoges in France; (2) soft porcelain, which was formerly made at Sèvres, near Paris; and (3) English porcelain, which, like the first, is made from kaolin and Cornish stone, but differs from it in containing calcined bones. For hard porcelain, the glaze is made from felspar, which contains a variable quantity of quartz, while in the glaze used for the other two there is usually some silicate of lead and borates, the presence of which allows of a lower temperature being used for the biscuited ware. Thirty-five firms in the Potteries make china, and 195 earthenware.

The population of the Potteries and of the district immediately round about is probably not less than a quarter of a million. It is estimated that there are from 46,000 to 50,000 people working in the Potteries, of whom 4703—viz., 3123 males and 1580 females—are engaged in what might be called lead or dangerous processes. In his Annual Reports the Chief Inspector of Factories shows that in 1898 there were 457 cases of lead poisoning notified to the Home Office from the Potteries, 249 in 1899, and 200 in 1900, whereas for the same periods the following numbers were reported from all other trades combined, excluding house painters, 1278, 1258, and 1058. The number of persons working “in the lead” in the Potteries in July 1898 was 4703, and were classified as follows:—

Number of Persons employed in Processes where Lead is used in the manufacture of Earthenware and China, North Stafford District, July 1898.

Persons Employed. Under 13. 13 to 18. Over 18.

Males. Females. Males. Females. Males. Females.

(a) Dippers ... ... 9 15 486 66

(b) Dippers’ Assistants 7 ... 408 49 103 58

(c) Ware Cleaners ... ... 15 76 90 382

(d) Glost Placers ... ... 58 8 1747 38

(e) Majolica Paintresses ... ... ... 62 ... 233

(f) Ground Layers ... ... ... 9 89 373

(g) Colour Dusters ... ... ... 24 7 118

(h) Enamel Colour & Glaze Blowers ... ... ... ... 9 12

|(i) Other persons coming in contact with lead, not enumerated in the foregoing list ... ... 19 13 76 44

Totals 7 ... 509 256 2607 1324

Males 3123

Females 1580

Total 4703

At the date of the Report on the Use of Lead in Potteries, presented by Professor Thorpe and myself to the Home Secretary (1899), the total number of cases of lead poisoning in the Potteries during the previous three years, i.e. since the Act of 1895, as to compulsory notification, came into force, was:—

Males 478

Females 607

Total 1085

These were distributed thus:—

Number of Persons reported as suffering from Lead Poisoning during the years 1896, 1897, and 1898.[67]

1896. 1897. 1898.

13 to 18. Over 18. 13 to 18. Over 18. 13 to 18. Over 18.

M. F. M. F. M. F. M. F. M. F. M. F.

Dippers 3 1 50 14 ... ... 48 9 ... 1 41 6

Dippers’ Assistants 9 6 3 12 26 2 3 8 14 2 6 17

Ware Cleaners ... 3 2 54 ... 2 ... 66 ... 3 1 55

Glost Placers 1 ... 57 1 ... ... 53 2 ... ... 48 1

Majolica Paintresses ... 1 ... 38 ... 7 ... 41 ... 4 ... 27

Ground Layers ... ... 16 34 ... ... 15 40 ... ... 10 45

Colour Dusters ... 2 ... 11 ... 9 ... 1 ... 6 ... 9

Litho. Dusters, or Cleaners in making Litho. Transfers ... 10 ... 11 ... 8 4 10 4 8 6 9

Other persons coming in contact with lead, not enumerated in the foregoing list ... 1 10 ... ... 2 25 5 ... ... 22 3

Totals 13 24 139 175 26 30 148 182 18 24 134 172

Age. 1896. 1897. 1898.

13 to 18 years. Males 13 26 18 = 57

Females 24 30 24 = 78

Over 18 Males 139 148 134 = 421

Females 175 182 172 = 529

Grand total in 3 years Males 478

Females 607

1085

Comparison of Number of Persons “Working in Lead” in July 1898, with number of cases of Lead Poisoning reported in year 1898.

Workers. Lead Cases.

Males. Females. Males. Per cent. Females. Per cent.

Dippers 495 81 41 8.2 7 8.6

Dippers’ Assistants 518 107 20 3.9 19 17.8

Ware Cleaners 105 458 1 1.0 58 12.7

Glost Placers 1805 46 48 2.6 1 2.0

Majolica Paintresses ... 295 ... ... 31 10.5

Ground Layers 89 382 10 11.3 45 11.8

Colour Dusters and Litho. Dusters 16 154 10 62.5 32 20.8

Other persons in contact with lead 95 57 22 23.2 3 5.3

Totals 3123 1580 152 4.9 196 12.4

These statistics were obtained for Professor Thorpe and myself by Mr J. H. Walmsley, H.M. Inspector of Factories, Stoke-on-Trent, and are reproduced from our Conjoint Report to the Home Secretary on Lead Compounds in Pottery. From these figures it is seen that of the total male workers 4.9 per cent. become “leaded,” whereas of the female workers, who form the smaller body, the proportion is as high as 12.4 per cent.; and if the official figures for 1897 had been taken, the results, it is believed, would have been even higher. Before Professor Thorpe and myself commenced our investigation of lead poisoning in the Potteries, Special Rules had been issued by the Chief Inspector of Factories in 1898, the good effects of which were already being felt at the time of our visits to Staffordshire. From the Annual Report of the Chief Inspector of Factories it appears that in 1900, 200 cases of lead poisoning in the Potteries were reported, as against 249 notified in 1899. Dr Morison Legge in alluding to this subject remarks that it is natural to attribute the diminution partly to the new Special Rules (1898), and to the fact that in some factories the use of raw lead has been discontinued. The numbers of cases of both sexes in 1899 are much fewer than in 1898; but of the total persons, it is to be noted that whereas females constituted 55.2 per cent. and males 45.8 per cent. during 1898, the reverse occurs in 1899, viz., 51.4 per cent. males and 48.6 females. The alteration in sex distribution among persons attacked is attributed by Dr Morison Legge to the medical examination, in which adult males did not participate. It would appear, too, that there is a diminution in the number of severe cases reported, a circumstance which is also attributed to the medical examination. The diminution is most observed among ground layers and colour dusters, but not in ware cleaning or dipping operations.

What are called the dangerous processes of pottery manufacture are those in which the worker is brought into contact with lead. The preceding tables show that from lead poisoning a very high percentage of colour and litho-dusters suffer, also that dippers’ assistants, ground layers, ware cleaners, majolica paintresses, and dippers run a considerable risk from plumbism. There are fewer women than men working as dippers, and in this department the incidence of plumbism is nearly equal in the two sexes. With the exception of glost placing, i.e. filling the ovens with the ware about to be fired, and which is heavy labour and only fit for men, females predominate in all the other departments. From these figures it is seen that males who are colour dusters suffer in much larger proportion from lead poisoning than do females, but in nearly all the other processes it will be observed that the percentage of lead poisoning is higher in females than males. It is the lead processes that have justly caused pottery manufacture to be regarded as one of the dangerous industries, and whatever may be said to the contrary, women, especially young women from seventeen to thirty years of age, and all young males or females, are especially susceptible to plumbism. Lead poisoning in pottery manufacture has for long been known, but neither had the Home Office, nor employers and the public, any adequate idea of the extent to which the evil prevailed until industrial plumbism became notifiable. It was with the view of throwing light upon this subject that the Secretary of State invited Professor Thorpe and myself, in May 1898, to institute a special inquiry into the hygienic questions involved in the use of lead in pottery processes, and to ascertain—

(1) How far the danger may be diminished or removed by substituting for the carbonate of lead ordinarily used, either (a) one or other less soluble compound of lead, e.g. a silicate; (b) leadless glaze.

(2) How far any substitutes found to be harmless or less dangerous than the carbonate lend themselves to the varied practical requirements of the manufacturer.

(3) What other preventive measures can be adopted.

Professor Thorpe and myself, either singly or together, visited not only the potteries in Staffordshire and in Scotland, but several of the leading manufactories on the Continent, e.g. at Delft, La Louvière, Maastricht, Copenhagen, Charlottenburg, Dresden, Limoges, Choisy-le-Roi, etc., and our opinions and recommendations are embodied in a Blue Book which was presented to the Home Secretary, Sir Matthew White Ridley, in February 1899. These, it is to be hoped, will ultimately form the basis of legislation for the trade in this country. At present our recommendations have been challenged by the manufacturers, and are the cause of considerable dispute between the master potters of this country and the Home Office. I therefore reproduce our recommendations:—

(1) That by far the greater amount of earthenware of the class already specified, i.e. white and cream-coloured ware, can be glazed without the use of lead in any form. It has been demonstrated, without the slightest doubt, that the ware so made is in no respects inferior to that coated with lead glaze. There seems no reason, therefore, why in the manufacture of this class of goods the operatives should still continue to be exposed to the evils which the use of lead entails.

(2) There are, however, certain branches of the pottery industry in which it would be more difficult to dispense with the use of lead compounds. But there is no reason why, in these cases, the lead so employed should not be in the form of a fritted[68] double silicate. Such a compound, if properly made, is but slightly attacked by even strong hydrochloric, acetic, or lactic acid. There can be little doubt that if lead must be used, the employment of such a compound silicate—if its use could be insured—would greatly diminish the evil of lead poisoning.

(3) The use of raw lead as an ingredient of glazing material, or as an ingredient of colours which have to be subsequently fired, should be absolutely prohibited.

(4) As it would be very difficult to ensure that an innocuous lead glaze shall be employed, we are of opinion that young persons and women should be excluded from employment as dippers, dippers’ assistants, ware cleaners after dippers, and glost placers in factories where lead glaze is used, and that the adult male dippers, dippers’ assistants, ware cleaners, and glost placers should be subjected to systematic medical inspection.

These were our recommendations, and while they received a considerable amount of approval throughout the country, some of them, as might be expected, have been the subject of hostile criticism on the part of the pottery manufacturers. It should be borne in mind that a few years previous to our inquiry a Committee appointed by Mr Asquith, then Home Secretary, and composed of Mr S. W. May, H.M. Superintending Inspector of Factories (Chairman), Dr John T. Arlidge, Mr W. D. Spanton, F.R.C.S.E., Mr A. P. Laurie, M.A., Mr J. H. Walmsley, H.M. Inspector of Factories, and Mr W. D. Cramp, H.M. Superintending Inspector of Factories (Secretary), had reported to the Secretary of State, and made certain recommendations, including one specially by Mr Laurie, in which it is suggested that the manufacturers should be circularised from the Home Office to experiment with and test the uses and the effect upon the health of the workpeople of glazes and colours in which all the lead had been fritted; also the practicability of making a glaze that would be harmless to those employed in the manufacture, and at the same time would not injure the ware. It remains a cause of disappointment that, considering the assistance rendered by the 1893 Committee, the pottery manufacturers did so little to introduce the improvements that were recommended so as to minimize the evils that were yearly increasing. Periodical medical examination of the workers, male as well as female, they certainly encouraged, and they admit that the result was beneficial. There is a feeling that, had the manufacturers bestirred themselves a little more in the direction of using properly fritted lead compounds instead of raw lead in the glaze, and of again experimenting with leadless glazes to see what they could accomplish, plumbism in pottery manufacture would have materially diminished, our inquiry might not have been necessary, and certainly the recommendations made by Professor Thorpe and myself would not have been viewed, as they are by employers, in the light of a menace to the industry and a check to its commercial prosperity.

If there is one thing upon which the British public has made up its mind in regard to some of the important labour and social questions of to-day, it is, that there ought to be fewer cases of lead poisoning in the manufacture of pottery generally, and that plumbism should be practically abolished in the production of certain kinds of earthenware. It would therefore be rather to the advantage of the industry than otherwise, were the Staffordshire employers to meet the wishes of the public in this respect, by making a greater effort to produce ware dipped in leadless glaze. When the Home Secretary published our recommendations, and stated to employers that it was his intention to give effect to them, the pottery manufacturers assumed an attitude partly of agreement and partly of disagreement. They at once stated their willingness to discontinue the use of raw lead in glazes; they asked for a lengthened period to test and experiment with fritted lead, while in regard to leadless glazes they have taken up the position which, up to the time of writing, may be regarded as one of no compromise. The abolition of raw lead, if carried out, would mark a very important stage in the pottery manufacture of this country, and of itself would do much to reduce the number of cases of lead poisoning. The use of fritted lead compounds would also prove helpful; but in order to obviate the risks of plumbism from the use of these substances, the fritting of the lead compounds has to be done carefully, for although less soluble than raw lead, yet plumbism has followed their use. A simple silicate of lead possesses advantages over the carbonate, both in its physical and mechanical characters; it is, for example, less dusty and clammy than either white or red lead, and is more easily removed from the skin by washing. Such an ordinary silicate may contain as much as 70 per cent. of lead oxide, and 25 per cent. of silica, with small quantities of alumina, lime, magnesia, and alkalis, corresponding in fact to a crude mono-silicate, “and this compound, which is generally understood as ‘fritted’ lead, is hardly less soluble in acids than basic lead carbonate,” besides “glazes in which the whole of the lead has been fritted as a properly compound lead silicate—that is, fritted directly with the other components of the glaze, so as to form a double silicate—have been found to possess greater covering power than a glaze containing the same relative amount of lead in the ‘raw’ state, with the further advantage of enhancing the colour.” When the amount of silica is increased the fritt becomes more innocuous, but there is a limit to which silica can be added to litharge, so as to produce a homogeneous silicate. Even bisilicate of lead is not wholly insoluble in acids. Professor Thorpe found in his experiments, conducted in the Government Laboratory, that it was not desirable the fritted lead should be a simple silicate, also that a properly compounded double silicate could be made that would fulfil all the requirements of the potter, and at the same time be practically insoluble in acids. He suggested the following as a suitable constituent of glaze, and as a compound that would be only slightly attacked by hydrochloric acid, viz.—

Lead Monoxide 22.0

Alumina 7.5

Lime 8.3

Alkalis 3.9

Boracic acid 3.5

Silica 54.8

100.0

This combination can be obtained by “fritting an intimate mixture of litharge, flint, felspar, tincal, and chalk, or an intimate mixture of litharge, flint glass, borax, china clay, and ground flint; or, as is done on the Continent, a portion of the flint may be replaced by white sand, the colour if necessary being corrected by cobalt.” There is a very strong feeling that in Staffordshire the pottery manufacturers have been using more lead than is actually required to make a good glaze. Lead has been used without proper discrimination. As to what the amount of combined lead, calculated as oxide, which the glaze of “glost” ware should contain, the opinion of even practical potters is divided. It has been thought by some that 20 per cent. is required, while others fix the limit at 10. Professor Thorpe found excellent examples of lead-glazed ware in which the monoxide of lead did not exceed 12 per cent. of the total weight of the glazing materials, while on analysing some of the liquid taken from the dipping tubs in the potteries, he found the amount varied from 13 to 24 per cent., and even higher. If, therefore, the use of lead compounds is still to be permitted, and, as has been shown, fritted lead in the form of a simple silicate is not much less soluble than raw lead, it is apparent that, with the view of preventing injurious consequences, their use must be restricted and regulated. It was with this object that the Home Office insisted upon all fritted lead compounds conforming to a certain test of solubility, and it is around this point there is considerable disagreement between the master potters and the Home Office. In a Report on the “Use of Lead in the Manufacture of Pottery,” presented to the Secretary of State by Professor Thorpe (1901), the Government chemist deals, among other things, with the relation between the composition and solubility of lead silicate, as shown in the following table:—

Fritts arranged in order of Increasing Solubility. Oxide of Lead dissolved by 0.25 per cent. of Hydrochloric Acid. Percentage Composition. —— Oxide of Lead.

Per cent.

Preparation from Maastricht fritt (Belgium) None. 18.04

Preparation from Boch’s fritt (Belgium) Traces. 21.83

Boch’s fritt 2.6 22.44

Ålmström’s fritt (Sweden) 4.8 44.06

Maastricht fritt 5.6 18.97

Owen’s glaze fritt 6.6 16.23

Owen’s fritt 23.8 45.77

Doulton’s fritt 60.4 37.92

Owen’s lead silicate (No. 2 sample) 99.6 70.40

I have not reproduced in the table the percentage composition of the other ingredients of the fritt, but it is maintained that the solubility does not depend upon any of the constituents, nor does any single base or acid increase or decrease continuously as the solubility of the fritt increases. Although in a general sense the solubility increases with the sum of monoxides present in the fritt, yet there is no regular progression. The solubility, according to Thorpe, depends upon the value of the ratio bases/acids which, judging from the results obtained by him, should not exceed 1.45, or thereabouts, if the fritt is to be practically insoluble in 0.25 per cent. hydrochloric acid and be therefore safe. With the view of coming to some understanding upon this question a conference was held between representatives of the pottery industry and the Home Office on 31st October 1899. Two months afterwards the Secretary of State intimated that it was his intention to propose that after a certain interval a standard of insolubility for fritted lead employed in glazes should be observed by the manufacturers—the standard of insolubility being that the glaze should not yield more than 2 per cent. of lead when acted upon by hydrochloric acid, under certain conditions. Permission was granted to manufacturers to submit specimens of fritted lead to Professor Thorpe, so that they might have the necessary chemical assistance if wanted. Several samples were received, and on examination it was found that they could contain amounts of lead ranging from 24 to 53 per cent., and yet be capable of conforming to the standard of solubility required by the Home Office, although generally speaking they yielded slightly larger quantities of lead oxide to dilute hydrochloric acid than the insoluble silicate prepared from Continental fritts. In a short Report by Dr Thorpe, dated 20th November 1900, are published directions for the fritting of lead. The manufacturer, for example, “may, in the first place, fritt together all the materials given in the receipts—that is in one operation. If he chooses to take this course it would, as a matter of economy, be preferable to substitute litharge, if not for the whole of the raw lead, at least for the white lead. It seems absurd to pay for the trouble of putting the carbonic acid and water into the white lead, when these ingredients are expelled by the heat of the kiln. The required alteration in the receipt may easily be calculated from the fact that 1 lb. of litharge contains the same amount of lead oxide as 1.02 lb. of red lead or 1.18 lb. of white lead. Or the manufacturer may make up his fritt by commingling two other fritts. Thus he may fritt together borax, stone and flint, and fritt also the lead oxide, flint and stone, each in such proportions that the two when mixed with the whiting and china clay form a composition containing 18 per cent. of lead oxide.” It was urged by the manufacturers that the 2 per cent. solubility of lead in a glaze would be materially affected by the degree of fineness to which the fritt might be ground, but experiments showed that while within limits increased solubility of the fritt and fineness of grinding were concurrent, yet this question was rather of an academic nature, and had no practical bearing upon the use of fritted lead compounds in pottery. In our Conjoint Report, dated 1889, when discussing the amount of combined lead that might be allowed in glazes, we stated as the opinion of practical potters that it should be from 10 to 20 per cent. We ourselves suggested 12 per cent. Subsequent experience and experiment convinced Professor Thorpe that 12 per cent. is higher than is actually necessary in earthenware and china glaze. Nor does he regard the limit of 2 per cent. of solubility as too hard or stringent a requirement. The manufacturers pressed the Home Office to raise the limit to 5 per cent., but to do this in the face of existing evils was far from helping the object that the Home Office had in view. The stamping out of lead poisoning in pottery manufacture is a most desirable object, and one all must wish to see accomplished without, if possible, any injury to the trade. “If the limit is raised, as suggested, to 5 per cent., it means that the lead in an ordinary earthenware or china glaze, as at present used, may be so soluble that one-third of it may be extracted by very dilute acid at ordinary temperatures in one hour.” More than that, to raise the limit to 5 per cent. would be to throw away all the result of the experience that has been gained by experiments conducted over a period of three years, and would tend to perpetuate the evils that at present exist.[69]