Note 74 — Of the London Chimney-Sweepers. (continued 6)

Mr. Rammell supplies the following note on the use of “Poudrette.”

“In connexion with this subject,” he says, “a few observations upon the application of poudrette in agricultural process may not be without interest.

“With regard to the fertilizing properties of this preparation, M. Maxime Paulet, in his work entitled ‘Théorie et Pratique des Engrais,’ gives a table of the fertilizing qualities of various descriptions of manure, the value of each being determined by the quantity of nitrogen it contains. Taking for a standard good farm-yard dung, which contains on an average 4 per 1000 of nitrogen, and assuming that 10,000 kilogrammes (about 22,000 lbs. English) of this manure (containing 40 kilogrammes of nitrogen) are necessary to manure one hectare (2½ acres nearly) of land, the quantities of poudrette and of some other animal manures required to produce a similar effect would be as follows:—

Kilogr.

“Good farm-yard dung, the quantity usually spread upon one hectare of land10,000

Equivalent quantities of human urine, not having undergone fermentation5,600

Equivalent quantities of poudrette of Montfaucon2,550

Equivalent quantities of mixed human excrements (this quantity I have calculated from data given in the same work)1,333

Equivalent quantities of liquid blood of the abattoirs1,333

Equivalent quantities of bones650

Equivalent quantities of average of guano (two specimens are given)512

Equivalent quantities of urine of the public urinals in fermentation, and incompletely dried233

“M. Paulet estimates the loss of the ammoniacal products contained in the fæcal matters when they are withdrawn from the cesspools, by the time they have been ultimately reduced into poudrette, at from 80 to 90 per cent.

“I have not been able to meet with an analysis of the matters found in the fixed and movable cesspools of Paris, but in the ‘Cours d’Agriculture,’ of M. le Comte de Gasparin, I find an analysis by MM. Payen and Boussingault of some matter taken from the cesspools of Lille, and in the state in which it is ordinarily used in the suburbs of that city as manure. This matter was found to contain on the average 0·205 per cent of nitrogen, and thus by the rule observed in drawing up the above table, 19,512 kilogrammes of it would be necessary to produce the same effect upon one hectare of land as the other manures there mentioned. The wide difference between this quantity and that (1333 kilogrammes) stated for the mixed human excrements in their undiluted state, would lead to the conclusion that a very large proportion of water was present in the matter sent from Lille, unless we are to attribute a portion of the difference to the accidental circumstance of the bad quality of this matter. It appears that this is very variable, according to the style of living of the persons producing it. ‘Upon this subject,’ M. Paulet says, ‘the case of an agriculturist in the neighbourhood of Paris is cited, who bought the contents of the cesspools of one of the fashionable restaurants of the Palais Royal. Making a profitable speculation of it, he purchased the matter of the cesspools of several barracks. This bargain, however, resulted in a loss, for the produce from this last matter came very short of that given by the first.’

“Poudrette weighs 70 kilogrammes the hectolitre (154 lbs. per 22 gallons), and the quantity usually spread upon one hectare of land (2½ acres nearly) is 1750 kilogrammes, being at the rate of about 1540 lbs. per acre English measure. It is cast upon the land by the hand, in the manner that corn is sown.

“Poudrette packed in sacks very soon destroys them. This is always the case, whether it is whole or has been newly prepared.

“A serious accident occurred in 1818, on board a vessel named the Arthur, which sailed from Rouen with a cargo of poudrette for Guadaloupe. During the voyage a disease broke out on board which carried off half the crew, and left the remainder in a deplorable state of health when they reached their destination. It attacked also the men who landed the cargo; they all suffered in a greater or less degree. The poudrette was proved to have been shipped during a wet season, and to have been exposed before and during shipment, in a manner to allow it to absorb a considerable quantity of moisture. The accident appears to have been due to the subsequent fermentation of the mass in the hold—increased to an intense degree by the moisture it had acquired, and by the heat of a tropical climate.

“M. Parent du Châtelet, to whom the matter was referred, recommended that to guard against similar accidents in future, the poudrette intended for exportation, in order to deprive it entirely of humidity, should be mixed with an absorbent powder, such as quicklime, and that it should be packed in casks to protect it from moisture during the voyage.”