SEVERAL METHODS OF MAKING SALT-PETRE, RECOMMENDED TO THE INHABITANTS OF THE UNITED COLONIES, By the Honorable CONTINENTAL CONGRESS. AND Re-published by Order of the GENERAL ASSEMBLY OF THE Colony of MASSACHUSETTS-BAY.
Together with the RESOLVE of said Assembly.
AND AN APPENDIX. By Doctor WILLIAM WHITING.
WATERTOWN. Printed and Said by BENJAMIN EDES, near the Bridge, 1775.
IN CONGRESS.
WHEREAS the safety and freedom of every community depends greatly upon having the means of defence in its own power, and that the U [...]ited Colo [...]ies may not, during the continuance of th [...]ir present important conte [...] for Liberty, nor in any fu [...]ure time, be under the expensive, uncertain and dangerous necessity of relying on foreign importations for Gun-Powder: And it being very certain from observation and experiment, that Salt-Pe [...]re is to be obtained in great abundance from most par [...]s of this Northern Continent; that the surface of the earth, in long used tobacco ware houses and their yards, or of common tobacco-houses, is particularly and strongly impregnated with Nitre.
Resolved, That it be recommended to the Provincial Conventions of the tobacco Colonies, that as quickly as may be, they appoint one or more manufactories on each river, contiguous to the great inspection [...], and under the direction of persons qualified by their skill and diligence to bring this important business to a speedy and successful issue.
[Page 4]To the Assemblies and Conventions of the other Co [...]nies, it is recommended immediately to put in practice such other mode of making Salt-Petre, as may be [...]ound best adapted to their respective circumstances.
That all persons may be encouraged to apply themselves to the manufacture of Salt-Petre, it i [...] recommended to the several Assembles and Conventions to buy up, on account of the United Colonies, all the good and merchantable Salt-Petre at half a dollar fo [...] each pound, that is, or shall be made in t [...]eir respective Colonies before the first day of October, 1776.
It is recommended that the collecting Sulphur be encouraged:—And it is recommended to the several Pr [...]vincial Conventions, to grant such premiums, for the refining of Sulphur in their respective Provinces, as ma [...] be judged proper.
A [...]d it is further recommended to the several Assemblies and Conventions that they cause mills to be erected, and skilful persons to be procured and employed for making Gun-Powder.
As Salt-Petre is a [...] article so necessary for defence, and in other respects so extensively useful, it is an object that not only requires the public patronage, but demands the attention of individuals: The following systems or methods of making Salt-Petre, suited to different circumstances and different materials▪ is recommended to the a [...]tention of the good people of these United Colonies.
SALT PETRE is to be found in tobacco houses, stables, cow houses, hen, and pidgeon houses, and in any covered place, where the influence of the Sun seldom reaches. A sixty feet tobacco house will yield upwards of sixteen hundred weight a year, and so in proportion for larger or smaller houses. In order to prepare the fl [...]ors for attracting Nitre, all dung and other tr [...]sh mu [...] be removed; and if the floors are not level, they must be made so by laying on marle, or any soil n [...]t too s [...]ff, which must be lightly [...]rod down with their feet. The floor being thus prepared, sprinkle strong amber over it, made from tobacco trash, and cover it with wet ground leaves, or other tobacco trash for a fortnight; then clean out the trash, and in any co [...]l dry morni [...]g that succeeds, you will find on the floor the Nitre attracted and condensed like hoar frost; sweep this off [...]ightly, and put it by in hogsheads, or other safe place in a hou [...]e, until you have leisu [...]e to go through the following process: This wo [...]k you must carefully repeat as of [...]en as you observe the abovementioned appearance of Nitre on your floors; by which means you will soon be furnished with a competent quantity to employ a leisure day.
Process. MAKE a lee from this earth, in the same manner as is usually done for soap, no [...]ing that the earth is not to be hard packed on the straw in the bo [...]tom of your lee vessel, which would retain the water to be poured on it too long, and overcharge it wi [...]h saline particles, to the great interruption of the process: Place the earth hollow in the vessel, for the reception of the water; the first put to it must be warmer th [...]n new milk from the cow, afterwards add cold water; fix a vessel to receive the lee as soon as you begin to put the wa [...]er in, as it will not remain long upon the earth, but in a few minutes b [...]gin to drop into the receiver; if it runs foul, it must be returned upon the earth; as soon as i [...] h [...]s dropped a g [...]llon, you may begin to [...]il it in a cast i [...]on pot▪ every bushel of ear [...]h will require near 8 gall [...]ns of water; con [...]inue to boil i [...] gently [...]til you have fully charged your pot with the le [...], and [Page 6] [...] will find the watry particles evaporate, until it is reduced to a thick oily consistence, shooting into small icy crystals, which you will easily perceive, by exposing the fuds in a spoon to a cold place, then put the liquor out of the pot into w [...]ted wooden trays, and set it by in a [...]ool place for the first growth; if you accidentally boil it too thick, add a little cold water▪ when your trays have stood with the suds a few hours you mu [...] raise one end to let the lee drain off from the Salt Petre, which is the first growth, and which, by boiling a second time, will yield you a fresh quantity. After it is thus drained and become dry, you may put it into casks or tubs, until you have leisure without prejudice to your crops, to refine it.
To refine Salt Petre. P [...] into your pot about a third of the quantity your po [...] will hold of this first growth, and set it over the fire: you are to be provided with an iron rod or p [...]ker to stir it; as soon as it begins to melt, you will see it begin to boil furiously: keep it well stirred down, as at this time it is very apt to t [...]ke fire, which will destroy the whole; when you observe it in the boiling to look of a dirty white, slaken your fire, and stir it briskly for a quarter of an hour; then increase your fire and continue the stirring; though the danger of burning it is now over, the pot, before it is sufficiently melted, will be of a fleming red at the bottom, and the matter will appear like boiled cream; and when i [...] becomes whitish and liquid, pour it upon a stone, or some earthern vessel or a hard well rammed earthen floor, clean swept. As soon as it is cold, it will become hard; and if you throw it upon a stone, will ring like broken China. If you have not leisure immediately to clarify it, put it into a tub in a dry place, until some convenient opportunity.
To clarify coagulated cream of nitre.
To every pound of this matter put 6lb. of water, after you have broke it into small pieces, put your pot upon the fire, and stir it until it is well dissolved, then make the fire all r [...]und the pot, which will cause it to b [...]il in the middle, and prevent any waste by its drying and sticki [...]g on the sides of the pot; and as soon as the earthy ma [...]ter begins to set [...]e in the pot p [...]ur the liquid into a tray or other open v [...]ss [...]l, that its sediment m [...]y settle, pour off the clear liquor, and evaporate it with a gentle fire, until in a sp [...]n [Page 7] it will shoot into chrystals, then pour it into a tray, with dry sticks sixt across, so as to be a little below the surf [...]ce of [...]he liqu [...]r; set this by in a cool place, where it may stand until it shoots in [...]o clear transparent crystals, then gently pour off the liquor, and set the tray so as to drain i [...] off perfectly dry. Thus your salt petre is compleatly m [...]de, and in a few days will be dry enough to remove out of your tr [...]ys into [...]sks or v [...]ssels propor [...]ion [...]d to the quantities. The liquor you last poured off, must be again evapora [...]ed over the fire, for it will yield salt petre equally as good as the former; and thus continue the operation until all the watry particles are totally evaporated.
N. B. The e [...]rth from which you have extracted the s [...]lt petre, and all the w [...]tings of your v [...]ss [...]ls, if you lay it by [...]inly spread in y [...]ur h [...]use, will turn to profit, as it c [...]ntinues to be peculiarly proper to attract and absorb the nitr [...] floating in the air, and also the ear [...]hly matter which settles in the refining; and should y [...]u be in want of house-room, you may spread i [...] upon the ear [...]h, covered in the ma [...]ner that fodder s [...]acks are; it will produce salt-petre full as well as a tobacco house, taking [...]are that the [...]orth end be always open and defended from rain.
Method of making Salt-Petre at Hanover, 1766.
The salt petre works are within two miles of the town, they consi [...] of a house, that had probably been an old wooden barn; it had an ear [...]hen floor, on one side wi [...]hin stood a row of c [...]sks open at top, filled with earth▪ and under each c [...]sk a tub to receive what water p [...]ssed through the earth in the casks; on the other side was an iron kettle set in brick-work which might b [...]il at once, perhaps, two or three barrels of water; at the end fu [...]thest from the fire-place, the floor was dug deeper about four feet; in this part as a cooler place, there were tubs of the boiling liquor, set to chrystalize. The ground belonging to the house, perhaps an acre and an half, was filled with what we should call mud walls;—they were three feet thick at the bottom, and tapered up to one foot at top; heighth about five feet; these are placed so near each other that there is only room for a wheelbarrow to pass between: They are composed of street dirt and the rubbish of old [...]uildings, such as plaister, mortar, &c. they are exposed to [Page 8] sun, wind and rain. * Four persons were all the famil [...] that managed these works; an old woman was the sk [...]llfu [...] person who conducted the whole; her husband and a servant man were labourers, a servant maid sometimes assisting. The women attended to the boiling and chrystalization▪ the business of the men was to sh [...]ve off with a sharp spade, about a quarter of an inch of the surface of the earthen walls, and bring it in wi [...]h the wheelbarrow, then fill the casks with it, and fe [...]ch water to pour on it in the casks: they also emptied such casks as had been drained off all their virtue, and carried out the earth, plaistering it up again on the walls it was shaved from to fill the emptied c [...]sks. Thus in the course of a summer they went round all the walls; the first water that passed through the earth was that which was boiled; the second was reserved, being weaker, but having some virtue in it, to be poured on fresh earth. This works supplyed all the Electorate of Hanover with Salt-Petre. All the gun-powder for the King's troops 12000 men, the forts &c. was made from this Salt-Petre. The house and utensils could scarce be worth above £. 50 sterling.
An Account of the manufactory of Salt-Petre by Benjamin Rush, M. D. professor of Chemistry in the college of Philadelphia
It has long been an opinion among chemists and natural historians, that salt petre is a natural production. It has been said to be found in large quantities on the surface of the earth in Persia, India and China, where it is said to impart a coldness to the atmosphere; but some late enquiries give us reason to suspect that the whole of these accounts are without foundation. They were prob [...]bly propagated by the natives of these countries, only to preserve in their hands the manufactory of so useful an article of trade. All the Salt Petre which is imported from the East-Indies is made by art. I would not be understood to mean, that this salt is never found in a native state. It is sometimes found adhering to large rocks. It is likewise found in a native state under the arches of bridges, and in vaults, or [Page 9] wine cellars; but in these places it is found in such small quantities, that we are seldom at the pains of collecting it. It is found in a larger quantity in a native state in s [...]veral plants; but of this I shall say more hereafter.
The manufactory of salt petre is now no longer confined to the East Indies, but is carried on with equal advantages in many parts of Europe, particularly in Germany and France. I sh [...]ll mention the several processes which are used for this purpose in each of th [...]se countries.
C [...]ommar, a German chemist of c [...]nsiderable note, recommends the following meth [...]d of making Salt Petre, which he says is practised with great success in many parts of Germany▪ He orders lime, rubb [...]sh of all kinds, garden mould, and [...]shes to be mixed together, and moiste [...]ed from time to time with urine, care b [...]ing taken to stir them fr [...]qu [...]ntly. They should be all put into a small house▪ wi [...]h a window towards the north east. He does not direct as some have supposed▪ to leave this house open towards the north east, because [...]he ni [...]ous particles are brought from that quarter, but b [...]cau [...]e the winds from the nor [...]h east in that country, are generally accompanied with that temperature of the air, which is most greeable to the formation of the nitre▪ * In a few months; this mass will be so much impregnated with Salt, that one pound of it will yield two ounces of the Ni [...]re.
The King of Prussia was early sensible of the importance of a Salt Petre Manuf [...]ct [...]ry in his dominions, and has theref [...]re for this purpose always ob [...]iged his farmers to build their f [...]ces of common earth, mixed with a quantity of straw and dung. These substances corrupt in the course of a few years. The [...]ences are then sh [...]ved, or wholly taken down, and afford a large quantity of Salt Petre.
The sweepings of [...]he streets of a si [...]gle village in Hanover, afford all the Salt Petre that is used in the whole of that electorate. Dr. Franklin, from whom I received this piece of information, assur [...]d me, that the manufactory of the Salt-Petre from the above-materials was so simple, that [Page 10] it was carried on entirely by an illiterate old man and his wife.—The greatest part of the Salt Petre that comes from India is obtained nearly in the same manner. It is prepared entirely from the [...]ffals of the city of Patna
Mr. La Roux of the academy of Rouen informed me, that the following receipt had been found to answer very well in many parts of France for the manufactory of this salt. It is taken from Glauber, a German Chemist, I sh [...]ll deliver it in his own words.
"I will shew a way to such as have no inheritance left them from their parents▪ not have any thing to come to them by marriage, by what means they may, wi [...]hout labour or trouble, get a treasure for their children;—
"First, Let such a one take care to have some shade or hovel made, to j [...]in to that side of his dwelling that lies in the middle betwixt the north and east part of heaven, or some other more convenient place, so as to admit the sun and air to it, but to ke [...]p off the rain. Under this penthouse or hovel, let him dig a large pit, and wit [...] the earth he digs out, let him make banks r [...]und the [...] mouth, so that it may keep the rain off on every side▪ Thi [...] done, let him each day, in every year, or whensoever he can conveniently, carry and throw into that pit these following matters, so long till his nec [...]ssity fore [...]th him [...]o dig all [...] again, and see how much treasure he has got, even wh [...]le he slept. Now these matters are all sharp and [...]itter herbs, growing in by places, amongst b [...]sa [...]s, and on the way side, and such as beasts feed no [...] on, as efula, cicu [...]a, or hemlock, he [...]bane, fumatory, the thick stalks of tobacco, that are thrown away in those places where it is planted, the hard stalks of colwort, which the beasts eat not of, and likewise all those things they leave in their troughs; likewise [...]ir [...]ops or apples▪ if you have them at hand; also the leaves that fall from the trees in autumn are to be gathered; also pidgeons d [...]g. [...]ens dung birds and hens feathers; the ashes which women generally make their lee [...] with▪ and other ashes that is not [...]it for that use, as also [...]uch out of which the lee is already extracted; the [...]oot of chimnies, hogs hair, the horns of oxe [...] and cows, and the bones the dogs eat not of. All these matters may be thrown into this pit and that he may the sooner fill it, he may gather as much as he can from all the bordering places▪ and [Page 11] throw it therein, so that in one or two years time he may, with all th [...]se things fill up his pit: mean while, he must pour into the pit the urine gathered in his o [...]n house and that he may have enough he must get as much as he can from his neighbours, [...]o as to keep the things thr [...]wn into the pit in continual moisture, wh [...]r [...]by they may the so [...] er putrify. In want of urine common water may be take [...]; if sea water or other salt water can be had, it will be better. Also the brine of fishes pickle, and the salting of salt water that flesh is macerated (or pickled in) are of g [...]od use; also the blood of oxen, cows, calves, and sheep, which you may easily have at the butchers; all these things putrifying together, do put on the nature and property of Salt Petre.
"If now all these matters in your full pit shall h [...]ve well putrified, then cease from pouring on any moisture, and all the things are to be left so long until they are dried—then if you need money, let a salt petre maker be sought for, and bargain with him ab [...]u [...] the price of drawing off your Salt-Petre by water, of making it and selling it. This done, cast the remaining earth into a pit, together with the remaining lixivium that shot into nitre, and there leave it for a year or two, and moisten it sometimes with urine, or if you have not this, with comm [...]n water. This earth will again yield Salt Petre, but not half so much as at first."
But the greatest quantity of Salt Petre that is consumed in France, is prepared in Paris from the ruins of old stone buildings, p [...]dgeon houses, stables, and all such putrid masses of vegetable or animal matters as have been long covered.
The earth und [...]r the flo [...]r of old stables, mixed with a quantity of ashes, is a plentiful source of Salt-Petre. When this earth consists chiefly of clay, a quanti [...]y of s [...]nd or gravel should be added to it. The gravel or sand acts mechanically, by dividing the clay in such a manner as to suffer the water which is p [...]red on it▪ to pervade all its parts. All the composts which afford Salt Petre may be made to yield a fresh quantity of the salt by exposing them for some months to the air.
Nitre, b [...]sides being obtained by the artificial process we have described, may be obtained in a considerable quanti [...]y in a native state from certain plants. The tobacco is [Page 12] strongly impregnated with it * Those plants which contain Salt-Petre, always sparkle when they are thrown into the fire. But there is another less equivocal method of knowing whether a plant contains any quantity of this Salt. [Page 13] Bruise the plant well and press the juice from it; put th [...]se juice into an earthern pot, and place it in a cool cellar, fir [...] pouring a little sweet oil upon the surface of it, to prevent its becoming mouldy. If the plant contains any Nitre, you will find it in the form of crystals on the sides of the vessel, in six weeks or two months.
The method of extracting the Salt Petre is nearly the same, whatever ingredients we may employ for making it. The ingredients are put into tubs, barrels or hogsheads, perforated at their bottoms. Rain, river, or very pure spring water is poured upon them, which gradually dissolves all the salt they contain, and conveys it drop by drop into vessels provided to receive it. The Nitre in this state contains a large quantity of common Salt. Before I explain in what manner this Salt is to be separated from the Nitre, it will be necess [...]ry to premise that bare evaporation, by b [...]iling or otherways, will chrystalize common Salt, but that co [...]d and rest are necessary to chrystalize Nitre. The Lee, (if I may so call it) made from the materials which yield Nitre▪ is put into a large copper vessel, and is gradually boiled away, till chrystals of common Salt begin to form in it. These are taken out with a ladle as fast as they form, and thrown into a large basket, which stands directly over the vessel in which the liquor is boiling—when no more chrystals of common Salt can be found, and when a pellicle begins to be formed on the surface of the liquor, it is taken off the fire, and emptied into a number of copper or earthen pans, in a cellar, in which it soon shoots into chrystals of salt petre. The salt has now undergone its first degree of purification. As a quantity of common salt still adheres to the chrystals of ni [...]re, it is necessary to dissolve them in pure water and boil them in the manner we said before. A much less quantity of common salt is obtained now than formerly The nitre, after its second chrystalization, is used chiefly for the purposes of medicine, [Page 14] and caring provisions. But there is a third degree of p [...]rification n [...]cessary, before all the common salt c [...]n be com [...]pleatly separated from it. It is carried on in the s [...]m [...] manner ss the former [...] were. The [...]a [...]t petre is now [...]i [...]shig [...]st sta [...]e of purity, in which state only it is used for the manufact [...]ry of Gun Powder.
I cannot conclude this memoi [...] without observing, that the climate and productions of the middle and northern colonies of North-America render them ex [...]remely proper for the manufactory of salt pe [...]re. And the success which has attended several experiments in that way gives us reason to believe that it may be carried on in this country, with as great advantag [...]s as in France, Germany, or the East-Indies.
In the House of REPRESENTATIVES, Watertown, August 23, 1775.
WHEREAS the honorable CONTINENTAL CONGRESS h [...]ve strongly recommended to the Assemblies and Conventions of the United Colonies, to appoint one or more person or persons in each Colony to put in practice the making Salt Petre, according to such mode as shall be best adapted to their particular circumstances and to buy up on account of the United Co [...]onies all the good and merchantable Salt-Petre, that shall be made in said Colonies, by the first day of October 1776.
Therefore, in compliance with said recommendation, and for the carrying so valuable a purpose into execution, —It is RESOLVED That Dr. Whiting, Deacon Baker of Bolton, and Capt John Peck be a committee; whose busi [...]ess it shall be f [...]i [...]hfully and diligently to apply themselves to the manufacturing of Salt-Petre, for the space of three months from the first day of September, 1775; [Page 15] j [...]intly or severally, in such places in this Colony as they shall judge most suitable for that purpose:—And they are hereby directed to use all diligence to discover the most eligible and successful method of manufacturing that important commodity, and to communicate all the useful knowledge they shall acquire in said busin [...]s [...] to all such as request it of them:—And that th [...]y (from t [...]me to time) publish in the news papers or otherwise, all the us [...]ful discoveries they may make in the progress of said busines [...]; and each of the said committee shall be allowed and paid out of the public treasu [...]y of this Colony, for the said term of three months, four shillings per day, for every day they shall be employed in said service, as a reward for the aforesaid services.
And it is further RESOLVED, That said committee are hereby impowered to buy up all the good and merchantable Salt Petre that shall be made within this Colony, by the first day of said October, 1776, at half a dollar a pound: And the said committee are also directed to buy up all the good and merchantable Sulphur that shall be re [...]ned in th [...]s Colony by the first day of said October, at nine pence per pound; the sellers of Sulphur producing a certificate from a major part of the select men, either of the towns to which he or they belong, or the town where [...]ch Sulphur was refined; certifying that the same was produced and refined from mines and ores within this Colony▪ and that said committee shall deliver such Salt Petre and Sulphur to such person or persons as sh [...]ll be appointed by the General Court to receive the same; and shall receive out of the Colony treasury from time to time, such sums of money as upon representation, made to them by said committee, they shall judge necessary for buying up said Salt Petre and Sulphur▪
And it is further RESOLVED, That it be strongly recommended to the inhabitants of the several towns in this Colony, that they exert themselves in promoting this important manufacture (as the surest means of preserving their own lives, liberties, and estates, of insuring the salvation of th [...]ir country and i [...]s future prosperity) by erecting one or more Salt-Petre works in each town where it may be done with probable success; and that they not only thoroughly attend to the working up of those materials from [Page 16] which Salt-Petre may be speedily procured, without any previous management; but [...]hat th [...]y also take especi [...]l care to collect together under pr [...]per sheds, [...]hose m [...]teri [...]ls (the knowledge of which may be easily ob [...]ained f [...]m publications) which by fermenting and pu [...]ifyi [...]g together will in due time afford Salt Petre with ease and in grea [...] plenty.
And it is further RESOLVED, That the several methods of mak [...]ng Salt-Petre, recommended by the honorable Continental Congress, to the Uni [...]ed Colonies, be immediately re-printed, together with the foregoing Resolves; and that there be added thereto, by way of Appendix, the method of making Salt Petre, practiced by Dr. Graham —And that one of the pamphlets be sent to the select men of each [...]own within this colony; and that Dr. Whiting procure the [...]re printing the several methods recommended by the honorable Continental Congress for making Salt Petre, together with the foregoing Resolves, and distribute them agreeable thereto.
- James Otis,
- W. Sever,
- B. Greenleaf,
- W. Spooner,
- Caleb Cushing,
- J. Winthrop,
- R. T. Paine,
- Jed Foster,
- Enoch Freeman,
- Eldad Taylor,
- Benjamin Lincoln,
- M. Farley,
- S Holton,
- Cha. Chauncy,
- Benja. White.
A true Copy,
APPENDIX.
The following Method was communicated to me by a very worthy Gentleman, viz Doctor GRAHAM, of Westchester County, in th
[...] Colony of New-York, who (by the help of a German Servant) made in this Manner between Eight and Nine Hundred Weight of good Salt-Petre in one Season, viz.
HE procured the earth from under old buildings, which had no cellars; but he always avoided stables, and all other places, where the earths were impregnated wi [...]h urinous and excrementici [...]us salts: He pref [...]rre [...] the earths from under the oldest buildings and such as sme [...]l [...]d strong, and had somewhat of a bitterish or allum taste upon the tongue; with those kinds of earth he filled six half hogshead tubs, being previously carefully fixed for leech tubs, in the s [...]me manner as in drawing lee f [...]r soap or pot ash: he [...]lled them near full of earth, which he left ho [...]lowing on the top; he then filled his tubs with light s [...]ring or river water, letting them stand twenty-four hours, that the salts might be thoroughly dissolved: he then drew off the liquor into receivers placed for that purpose, and if the first running was [...]oul, he returned it on to the earth again▪ until it came through clear.—When he had procured forty gallons of this Lee, he put it into a brass kettle for boiling; he then put water on the tubs as before, letting them stand other twenty four hours; he then drew it off, and put this [Page 18] second running on to the next fresh tub of earth, and so on successively. When he had filled his kettle wi [...]h forty gallons of lee [...] as above ment [...]oned [...]he boiled it down u [...]til half was consumed. He then [...] a half b [...]rrel tub and fixed it for a leech, which [...]e filled near full of ashes, on which he poured the liquor just boiled; after he had run it through this, which he called his fi [...]tering tub▪ he again boiled it down one ha [...]f, which brought it to ten gallons; he then ru [...] it [...]g [...]in through the same tub of ashes▪ which ashes he never changed thr [...]ugh the whole course of his maki [...]g: he then boiled down the liquor the third time one half, which brought it to five gallons. He then poured the liquor into cedar kelors, made very flaring, holding 6 or [...] quarts each, and then set it in a cool ce [...]ar, where it would (in about twelve hours) shoot into chrystals. The earth which he emptied out of his tubs, he laid in ridges under a shed, with a view ( [...]fter a certain time) [...]o work them ag [...]in. After the liquor had stood in his cooler a sufficient time to chrystalize, he gently [...]r [...]ed his kelers up an edge, so as carefully to drain off the liquor from the chrystals, let [...]ing them stand in that position until the chrystals were drained dry, which he then took out of the k [...]lers, a [...]d k [...]pt in a proper vessel, until he had procured enough for clarifying.—The liquor which he drained off from the chrystals, he always mixed with his next la [...]t b [...]iling —His method of clarifying was this, (viz.) When he had collected chrystals sufficient to fill a b [...]ass kettle holding about two pail [...]ulls, he fi [...]led it near full with them; the [...] c [...]vering them with water▪ he put them over the fire, and raised the [...]eat u [...]til the chrystals were all dissolved; he then set the kettle in a cool cellar, where the nitre would ag [...]in shoot into chrystals, much more solid and pure than before; after which he drained off the liquor carefully as before a [...]d then turned o [...] the Salt-Petre in form of a large cake, which was now fit to p [...]ck up for sale.
This account I had from the gentleman's own mou [...]h, and in [...] thr [...]gh six of the u [...]ited col [...]ni [...]s in quest of knowledge in [...] I could hear of no [...] with [...] like success. The [...] of the directors of the l [...]rge [...] works at Philadelphia▪ [...] [Page 19] to those under other buildings; but upon making the exp [...]riment, I found such a mixture of common salt with the nitrous as to render the process qui [...]e unprofitable, notwi [...]hstanding I endeavoured carefully to follow his directions of d [...]pping out the common sal [...]s while the liq [...]r was boiling. However, there is not the least doubt but that the earth under these places which have forme [...]ly been used f [...]r stables, but have been for several years neglected, will afford plenty of salt-petre.—It is to be observed, that all earths are not equally susceptable of nitrous salts, therefore we sh [...]ll find the earth under some old buildings plentifully abounding with salt-petre, or nitre, whilst others are almost wholly destit [...]e thereof: so that it will be the surest way to try a small quantity of the earths under those buildings which are pitched upon as promising, by taking (for instance) half a bushel of the earth, put to it water in a sm [...]ll leech tub properly fixed, so as to draw off about two gallons; boil this down, and filter it through a small quantity of ashes, by the same rule as is directed for forty gallons, which rule will serve for any quantity whatever. But it may be observed here, that we have the greatest reason to doubt the gentleman's rule of boiling down all his liquors, so as to leave exactly an eighth part, before he set it to chrystalize.—It is natural to suppose that the earths under buildings are very various as to the quantity of nitre they contain, some being plentifully charged, whilst others are but lightly impregnated th [...]rewith. It is also certain that the nitrous sal [...]s must be concentrated to a certain degree, before they will chrystalize; or in [...]her words▪ the water that contains these nitrous salts mu [...] [...]e so far evaporated as [...]o bring the saline particles within the sphere of each other's attraction, before they will unite and run together in chrystals; there [...]ore it may (though I believe bu [...] seldom) happen, that the liquor may be fit for chrystalizing bef [...]re it is reduced to one eighth part; but that which will happen much more frequently is, that the nitrous salts will not be sufficiently concentra [...]ed for chrystalizi [...]g u [...]on boiling down to an eighth part; in that case, it will be n [...]c [...]ss [...]ry to continue [...] boiling until by setting some of the liquor in a cool place in a spoon, or dropping [...] few d [...]ops on a cold iron, you [...]ind it shooting into small chrystals, or some part of i [...] congealing like ice on the iron, [Page 20] or at least until a particle or hard scum forms on the top of the boiling liquor.
Although I purpose to avoid entering into an abstruse definition of Salt Petre, yet it will be proper just to observe, that this substance is rationally supposed to be compounded of three different materials, (viz) a nitrous acid, a volatile animal salt, and these two fixed, blended together and petrified by a vegitable or mineral alkaline salt, and thus form what we commonly call Salt Petre.—This short definition of salt-petre will serve to shew the propriety of Mr. Glauber's collection of materials recommended in the forgoing processes; and it is ardently to be wished, that every gentleman who heartily desires the salvation and prosperity of America, would exert himself in encouraging and forwarding such kind of collections as soon as may be throughout this Colony.
But the question will very naturally arise, to know from whence the earths made use of in the f [...]regoing process, could derive either their volatile, annimal, or their vegitable alkaline salts.—It is no ways unnatural to suppose that as those earths had imbibed their nitrous qualities from the air which had found its way to their surfaces, so they might also receive from the same air a sufficient quantity of animal volatile salts, which had been exhaled from animal carcases and excrements, always putrifying on the surface of the earth. As to the vegitable alkaline salt, which is said to be the basis of Salt Petre, I should not have expected a sufficiency from the unchanged filtering tub of ashes, which was all the alkaline that gentleman made use of. However, experiments may be very easily tried, to determine this matter, by mixing a small quantity of lime or ashes with a tub of the above earth, before it is lixiviated, and then lixiviating the same qu [...]ntity and kind of earth, without either lime or ashes, and see which produces the most Salt Petre.