Part 3 / Book 4 — Lecture IV. - Marine salts

A DISCOURSE Concerning the ESSENTIAL and MARINE Salts of Plants.

Read before the Royal Society, December 21, 1676.

CHAP. I.

In which is shewed the way of making both an ESSENTIAL and a MARINE Salt, out of the LIXIVIAL Salt of a Plant.

OMETIME since, I took the boldness to present my thoughts to this Honourable and Learned Body in a Discourse concerning Mixture. Wherein I have endeavoured to lay such a Foundation, as might hereafter reduce the Doctrine hereof to Experience and Practice; and to demonstrate, the Power and Use of Artificial Mixture. And in further proof of what is therein asserted, I have since made a continuation of Experiments upon the same Subject, in Two Methods. One in the Mixture of several Menstruums, both Acid and Alkaline, with all Sorts of Bodies. The Other, by calcining them, or, as it were, mixing them with the Fire.

2. §. I shall now proceed to a Third, which is, the mixing them with the Aer or exposing them to it; another of Natures grand Menstruums; which goes sometimes further than the Fire it self, in the dissolution of Bodies. This I have formerly mentioned for the Imitation of Nature, in producing a Marine or Muriatick Salt out of the Lixivial Salt of a Plant. Discourse of Mixture Ch. 5. Inst. 2. But some Learned Persons then present, seeming to doubt of the Experiment; I thought it requisite to prosecute the same a little further; that so, if possible, it might become clear and unquestionable. And because that Method was imperfect, and required half a year, or a longer time: I bethought my self of an other way; which proved far better, and more expedite. And which, withall, afforded me, not only a true Marine Salt, out of the Lixivial Salt of a Plant; but also another kind of Salt, different from them both: which may not be improperly called, an Essential Salt or Nitre of Plants. The History or manner of the production of them both, is as follows.

3. §. December 15. 1675, I took about half a pound of a strong Solution of the Lixivial Salt of Firne: and pouring it into an Earthen Pan, well glazed, broad and shallow, exposed it therein to the open Aer, in a Chamber Window, to evaporate of it self. Tab. 83.

4. §. This Solution or Lee, although it was very clear before, and having stood corked up in a bottle many days, had no sedement: yet standing now in the open Aer, within the space of 4 or 5 days, it began to let fall a very white Sedement, like fine Chalk; which encreased daily for 8 or 10 days; amounting at last to about half a Drachm of white, light and meer Earth, altogether insipid, and when it was well washed, stirring not upon the Affusion of Acids.

5. §. Within the space of a day or two after this white Sedement began to fall to the bottom; there was also gathered on the top, a kind of soft Scum or Cremor, wherewith the Solution was covered all over.

6. §. Within 8 or 9 days after the first exposing of the Liquor, or 2 or 3 days after the gathering of the Cremor; that Salt, which I take leave to call, an Essential Salt of Plants, began to appear; shooting into several little Crystals. These Crystals, as they grew bigger, began to sink, and at last fell down to the bottom of the Pan.

7. §. Upon their first generation or shooting, the said Cremor presently breaks, leaving a bare space round about each Crystal; and upon the bounds of every space is indented; Tab. 83. the space growing bigger and bigger together with the Crystal in the Centre. And so, by that time the Crystals are grown to a considerable number and bigness, the Cremor vanishes away, the several Circles or bare places breaking at last one into another all over the Surface of the Lee. After which, it never comes again.

8. §. From whence it seemeth, That the several Circles or bare Spaces about the Crystals, are made for the more free admission of the Aer, requisite to their Generation. For as there is no Crystal begins to be formed before there is a breach made in the Cremor: so that breach is enlarged together with the Crystal. So that as the falling of the Sedement and the gathering of the Cremor, sheweth that the Aer, as a Menstruum separates some part from the Lee: so the breaking of the Cremor afterwards, that as a Vehicle, it brings something to it: both in order to the Generation of the Crystals. Nature taking a Method for the Generation of simpler Bodies, as well as of those which are Compounded and Organical.

9. §. The Figure of these Crystals is angular and oblong, most of them about the fifth, sixth or seventh of an Inch; but none of them very regular. Yet we are not hence to conclude, but that with the help of some Circumstances which might be wanting in the shooting of these; some portion of regular ones may be obteined from this, as well as other Lixivial Salts hereafter mentioned.

10. §. They are somewhat transparent, and of a dark Ambar Color, or like that of brown Sugar-Candy. Of a quite different Taste from that of the Solution or Lee out of which they are bred; being not at all Lixivial, but very weak and mild; not Salt, but Bitter in a good degree.

11. §. It is also observable, that Alkaline and Acid Salts being both poured severally upon these Crystals, they stir not, nor are any way affected with either of them. So that these Crystals are no sort of Tartar, or Tartareous Salt. As is plain, from the manner of their Generation; Tartar being still bred in close Vessels; these never, but by exposing the Liquor to the Aer. As also from their Taste, being not sower, in the least, but bitter. And in that Tartar will make a Bullition with Alkaline Salts, which these will not do. Upon which accounts it appears, that they are a Salt different in Nature from all other Salts hitherto known, or a new Species added to the Inventory of Nature.

12. §. These Crystals within the space of about a fortnight after their first Generation, did also cease to shoot any more, but only increased a little in their Bulk. After which time, I dayly expected to see the production also of a true Marine Salt. And about two months after the said Essential Crystals had done shooting, and not before, this also began to shoot, in many small Crystals, and at the top of the Solution, as the other did, still falling to the bottom as they grew biger.

13. §. The Size of most of them was near that of the Flakes or Grains of Bay-Salt. The Colour of some of them white, of others transparent; and of others white in the Centre, with transparent Edges; as is also usual in the Crystals of Common Salt.

14. §. The Figure of most is a perfect Square, and of very many coming near to a Cube; which is also the Figure of Common Salt, and seldome an exact Cube. An exact Cube, being the constant property of no Marine Salt, that I know of, except that of the Dead Sea. Tab. 83. Divers of them were also raised as it were by several steps from a deep Centre to the Top: as is often seen in the common shooting of Common Salt; and not in any other. Their Taste is neither Lixivial, as that of the Solution out of which they shoot; nor bitterish, as that of the Essential Crystals; nor sowerish, as that of Tartar; but the perfect Taste of Common Salt.

15. §. It is also to be noted, That if Oyl of Vitriol, and some other strong Acids, be poured upon this artificial Sea-Salt, they make an Effervescence together: but if Spirit of Salt or Spirit of Nitre either be poured on it, though it be never so strong it stirreth it not. In both which, and all the formentioned respects, it answers to the Properties of a Marine or Common Salt, which no other Salt doth. I conclude it therefore to be a true Marine Salt produced by Art in the imitation of Nature.

CHAP. II.

Wherein is shewed, That the said ESSENTIAL and MARINE Salts of Plants are both of different Sorts.

AVING made the Experiment, that both an Essential and Marine Salt may be produced out of the Lixivial Salt of a Plant. I thought it probable, that neither the one nor the other, was always the same, but that as they had their general properties which made them to be of two general kinds; so they might have some special property, for the distinguishing of each kind into several Sorts. And withall, that in a warmer season, than before taken, the Tryal hereof might be finished in a shorter time.

2. §. For the making of which, I conceived it requisite to remove an Opinion which seemed to lye in my way; sc. That there is little or no difference between the several Lixivial Salts of Plants, as some Learned men have thought. But either there is a difference, or not: if not, it should be proved: and if there be, it should then be justly stated, what that difference is. For the doing of which, I chose this Method. I took an equal quantity of the whitest and purest Salts of divers Plants, all made by an equal degree of Calcination; and dissolved them all severally in an equal quantity of water. And pouring likewise an equal quantity, as about 10 or 12 drops of each into a spoon, I tasted them severally. Whereby it was very evident, that they were not all of one Tast, but of very different ones, both as to strength and kind: and therefore different in Nature also. The Salts I made tryal of were those of Sorrel, Anise, Wormwood, Mallow, Ash, Tartar and others: and upon half a Drachm of each I poured ℥ijß of water. The Solutions are here present to be tasted. By which the differences will easily be observed, and particularly that the Salt of Wormwood or Scurvygrass, is almost as strong again as the Salt of Anise, or Sorrel: and that the Salt of Ash is above twice as strong, and that of Tartar above thrice as strong, as that of Sorrel, and almost thrice as strong as that of Wormwood or Scurvygrass. So that he who shall give half a Scruple, suppose of Salt of Tartar; instead of half a Scruple of Salt of Wormwood, or other like Salt; he may as well give a Scruple of Rosin of Jalap, for a Scruple of the powder, or almost three Drachms of Rhubarb, or other like Purge, instead of one. And the like is to be said of other Lixivial Salts in their degrees.

3. §. Having observed thus much, I proceeded to repeat the former Experiment, with some of the aforesaid, and some other Vegetable Salts, the best calcin’d, and the purest, that could be made for this purpose, being these Six Salts, sc. of Rosemary, Garden Scurvygrass, Black Thorn, Common Wormwood, Ash, and Tartar. All which dissolved severally in fair water, I exposed in a Chamber window, and not in Winter, as before, but in the heat of Summer, sc. on the 19 of July, to evaporate of themselves.

4. §. The Effect was, That the third day after their being exposed, the Essential Crystals began to shoot in three of the Solutions, sc. in that of Rosemary, of Garden Scurvygrass, and of Black Thorn. On the fourth day, in that of Wormwood. On the fifth day, in that of Ash. In that of Tartar, not at all.

5. §. These Essential Crystals began, in all, to shoot at the top, and then to fall to the bottome; as in the Experiment before. But as there was very little of the white Sedement before mentioned, that preceded; So no Scum or Cremor at all. Which although a more perfect Calcination, it seems, did here almost prevent; yet did not in the least destroy the aforesaid Essential Salt, but rather make way for its more speedy and copious Production: exhibiting likewise a distinct Species in several of the Solutions.

6. §. For first, the Crystals of Rosemary (the largest of them) were about the bigness of a Rice-Corn. In Figure almost like a Tip-Cat, which Boys play with, split down the midle. Each Tip being cut into 5 sides all ending in a poynt: Tab. 83. the midle part divided into 7, all drawn by parallel Lines; the topmost with the lowermost but one, on each side, being three exact Squares.

7. §. The Crystals of Black Thorn are most of them poynted with just six sides of Equal Measure: very like to the shooting of true Crystal it self. Tab. 83. From the topmost of which six Sides, a Line being drawn out, runs parallel to a broad Base, whereon each Crystal stands. So that they are in some sort of a Rhomboid Figure.

8. §. The Crystals of Scurvygrass have also a very elegant and regular Figure, which is in a manner compounded of the two former now described. But they are nothing near so bigg, the largest of them, being no biger than a Grain of that which we call Pearl Barley.

9. §. The Crystals of Wormwood have also very many of them a regular Figure; but quite different from that of the Crystals before mentioned; each Crystal being a little Cylinder, saving that it is constantly somewhat smaller at one end, than the other: as it were one half of a Rowling-pin. Tab. 83. And not evenly Circular, but cut out by Six Sides of equal Measure: almost as in the Crystal of Nitre. So that contrary to what is seen in the forementioned Crystals, the ends of these of Wormwood are not poynted, but flat; and cut at Right Angles with the Sides.

10. §. The Crystals of Ash, though by their properties they appear likewise to be Essential; yet are nothing near so regularly figur’d, as all the forementioned.

11. §. The Colour also of the said Crystals is somewhat different: Those of Ash being of a brown transparency, almost like those of Firne. Those of Wormwood being also brownish, but paler. Those of Rosemary and Scurvygrass having some little Tincture, yet very clear. But those of Black Thorn without the least Tincture, and as clear as Crystal it self.

12. §. None of these Essential Crystals have any hot fiery Taste, but are very mild, and sensibly Bitter; especially, about the Root of the Tongue: as is also observable of some Plants hereafter mentioned, in speaking of the different Tastes of Plants.

13. §. Oyl of Vitriol droped upon these Crystals doth not affect them in the least: yet droped into the several Solutions out of which the Crystals are produced, immediately causeth a great Effervescence.

14. §. Of the Solutions above named, that, of Salt of Tartar was the 6ᵗʰ. Whereof it is remarquable, That having waited several Months together, I could not observe the least Essential Salt to be therein produced in all that time. Whether there be any other Vegetable Salts, besides this of Tartar, which will not yield the Essential above described, I have not yet experimented.

15. §. In the mean time, from the Premises it is very probable, that most of them afford more or fewer of the said Crystals. In regard they are Plants of a very different kind, which I made tryal upon: as Garden Scurvygrass, very Hot; Rosemary, very Aromatick. Wormwood very Bitter; Black Thorn, Astringent and Sower. And it is also plain, That the said Essential Salts contained in the Lixivial, are not altogether one and the same, but of divers Sorts.

16. §. ABOUT 7 or 8 days after the Essential Crystals were produced; the Marine Salt did also begin to shoot; first in Rosemary; quickly after, in Scurvygrass; Next, in Black Thorn and Wormwood, sc. after the space of a week or 10 days more. And in all of them with some difference of Size and Figure.

17. §. The plainest of all, was that produced out of the Salt of Black Thorn, consisting for the most part of very small Crystals, not above the 15ᵗʰ of an Inch square, as also thin, shaped like a Duch Tile used for Chimnies. Many others were very thick, and near to a Cube. Tab. 83. Most of which were a little hollowed in the midle, like a grinding Marble or Salt-Celler; and the hollow bounded by 4 plain and equal Sides, all descending a little towards the Centre; and measured by two cross Lines, which staid upon the four Angles of the Square, and so cut one the other at Right Angles. Both which Properties are likewise usually seen in the Crystals of Common Salt.

18. §. In Wormwood, many of these Crystals, besides the plain ones, were figur’d crossways like a Dagger-Hilt. Tab. 83. Which was sometimes naked, and sometimes inclosed in a square and almost Cubical Box. Many others were figur’d into Sprigs made up of four chief Branches standing crosswise, and those subbranched; and all the Branches made up of little square Crystals, clustered together in that Figure. The Sprigy Figure of these Crystals is not accidental, but hath constantly come after they had been three times dissolved, and the Solution exposed to evaporate.

19. §. The Marine Salt of Rosemary hath also some variety. For besides the plain ones above described, there are some thick Squares, Tab. 83. which have also a square hollow descending by five, six, or seven narrow steps, towards the Centre; being in Figure, saving these Steps, somewhat like the Hoper in a Mill.

20. §. Upon a second Solution of the same Salt, there shoots another sort of square; which is not plain on the edges, as the above-named, Tab. 83. but scalloped or florid all round about, not unlike the Leaves of some Plants.

21. §. The Crystals of Marine Salt of Scurvygrass are somewhat like to those of Rosemary now described.

22. §. As for the Lixivial Salts of Ash and Tartar, though in a Month or Five Weeks Space, they yield some Crystals of very clear Salt: yet of Marine Salt neither of them yieldeth the least particle. So that of these Six Lixivial Salts, sc. of Rosemary, Scurvygrass, Black Thorn, Wormwood, Ash and Tartar, all, but that of Tartar, yielded an Essential Salt. And all, but those of Ash and Tartar, yielded a Marine, such as is above described. All which Salts both Essential and Marine, together with their Models, made of white Alabastre, I have here ready to be seen.

23. §. Of those that yield these Salts, or either of them, it is further to be noted, That there is a considerable difference in the Proportion or Quantities which they yield. The Rosemary yields store both of Essential and Marine, but more Essential. Wormwood and Scurvygrass more Marine. Black Thorn less of Either. The Ash no Marine, and the Tartar neither the Essential nor Marine, as hath been said.

24. §. From what hath been said, I deduce only at present these Three Corollaies. First, That a Lixivial Salt, is not only a compounded Body sc. of Salt, Sulphur, Aer and Earth; but even a Compounded Salt, containing both a Vegetable Nitre, and a true Sea Salt.

25. §. Secondly, That the Exposing of Bodies, in the manner above shewed, may justly be accounted one Part of Chymistry hitherto Deficient, and much farther to be improved for the Discovery of the Nature of Bodies. For as Nature chiefly compoundeth Bodies by Digesting them, and so either shutting out or keeping in the Aer: So she Dissolveth them by Exposing, and so neither shutting in the Aer, nor keeping it out, but leaving it free to come and go; and thereby to bring, and carry off whatsoever is necessary for the Separation or Solution of Bodies. For the Sea it self (to confine the similitude to our present case) is but as a Great Pan, wherein all kinds of bodies being long exposed, are throughly resolved, ultimately yielding from the rest of their visible Principles, that which we call Sea Salt.

26. §. Lastly, if by Exposing and Dissolving we can make one Salt; then by Compounding and Digesting we may make another, yea any other Salt; either a Fixed of a Volatile, or a Volatile of a Fixed. That is to say, a Volatile Salt may be so separated from other Bodies, as to become Fixed; or a Fixed Salt may be so mixed with other Bodies as to become Volatile. For that any Salt should of it self become Fixed or Volatile, is a Fixion not grounded upon Experiment.

27. §. As for the Virtue of the Essential Salts above described, I believe they will be found upon tryal, not contemptible in some Cases. For which amongst other reasons, I have been the more punctual in relating the manner of their Generation; that others also may have the opportunity of making proof hereof.

28. §. When I made the Experiments for this and the foregoing Discourse, not having so good conveniency at home for making the Salts I used: I procured them all (except that of Firne, which I made my self) to be purposely prepared by Mr. John Blackstone a London Apothecary, who assured me of his great care herein; and particularly, that he added no Nitre to whiten any of the Salts with, as is commonly done for that of Tartar.

I do declare, That all the Lixivial Salts mentioned in this and the foregoing Discourse except that of Firne, were faithfully prepared by me

John Blackstone.