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.

SALT PETRE is to be found in tobacco houses, sta|bles, 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 re|moved; 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 o|ther 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 care|fully 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 em|ploy a leisure day.

Process. MAKE a lee from this earth, in the same man|ner 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 re|quire near 8 gall••ns of water; con••inue to boil i•• gently ••••til you have fully charged your pot with the le••, and

〈◊〉〈◊〉 will find the watry particles evaporate, until it is redu|ced to a thick oily consistence, shooting into small icy crys|tals, 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 with|out 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 ram|med 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 immedi|ately 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

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 quan|tities. The liquor you last poured off, must be again eva|pora••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 un|der 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 li|quor, 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 a|bout 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

sun, wind and rain.* 1.1 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 ser|vant man were labourers, a servant maid sometimes assist|ing. The women attended to the boiling and chrystaliza|tion▪ 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 im|part 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

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, recom|mends the following meth••d of making Salt Petre, which he says is practised with great success in many parts of Ger|many▪ 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▪ * 1.2 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 impor|tance 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 ta|ken down, and afford a large quantity of Salt Petre.

The sweepings of ••he streets of a si••gle village in Hano|ver, 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

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 prepar|ed 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 la|bour 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 pent|house 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 con|veniently, 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 hem|lock, 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; like|wise ••ir ••ops or apples▪ if you have them at hand; also the leaves that fall from the trees in autumn are to be ga|thered; also pidgeons d••••g. ••ens dung birds and hens fea|thers; 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 ga|ther as much as he can from all the bordering places▪ and

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 putri|fying 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 dri|ed—then if you need money, let a salt petre maker be sought for, and bargain with him ab••u•• the price of draw|ing off your Salt-Petre by water, of making it and selling it. This done, cast the remaining earth into a pit, toge|ther 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 gra|vel should be added to it. The gravel or sand acts mecha|nically, 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

strongly impregnated with it * 1.3 Those plants which con|tain 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.

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 con|tains 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 gradu|ally 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 di|rectly 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 cop|per or earthen pans, in a cellar, in which it soon shoots in|to 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 dis|solve them in pure water and boil them in the manner we said before. A much less quantity of common salt is ob|tained now than formerly The nitre, after its second chrystalization, is used chiefly for the purposes of medicine,

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 rea|son to believe that it may be carried on in this country, with as great advantag••s as in France, Germany, or the East-Indies.

By Order of the CONGRESS, JOHN HANCOCK, PRESIDENT.

Notes

• * 1.1

  THOUGH their mud walls were exposed to the rain in Hanover, yet it may be a question whether the heavy rain in America would not wash them too much, if on tryal it should prove so, they may be covered with a light shed.
• * 1.2

  The north east winds in North America, are generally accompanied with moisture, which render them improper for the formation of Salt Petre. The house which contain•• our Salt-Petre materials should therefore, in this country▪ ••e ••••posed to the north west wind••▪
• * 1.3

  EVERY one that has taken particular notice of the stalks of Tobacco th••t has been well cured, ••h••n bu••ning, must have observed a defl••gra••••••n of flashing exactly similar to that exhibited by Salt Petr•• when thrown upon coals. This phae|nomenon after I had frequently for many years observed at length induced me at a season of leisure to attempt making Ni••re out of Tobacco; which I did and I own i•• was with no small confidence of success, as I knew of no substance but Nitrous S••••ts, which deflagrated in that peculiar manner. I made therefore a strong ac••oction of tob••cco stalks, which, by a number of experiments. I f••und replete with two kinds of Nitrous Sa••ts viz. Nitrous Ammoni•••• and Nitrous Se|lenites the sa••e which are contained in the common mother lee of Nitre▪ In short notwithstan••ing I wasted a consi|derable part of the decoction by accidents and experiments, out of half a pound avoit dupots of dry tobacco stalks, I ob|tained (by adding pure fixed vegetable alkali, and disengaging the volatile a••kali and earth) about an ounce of true Salt-Petre: Which, however, was brown by reason of the oily parts of the sta••ks. Thus far I proceeded that time but for want of leisure have not as yet proceeded any further I beg leave, however▪ to recommend it to others, who may think it worth their while to labour for an improvement of this hint towards a Salt Petre Manufactory; and I would par|ticularly recommend it to the Tobacco Colonies, to consider whether it be not an object worthy of their serious attention; for I own I am so sanguine as to believe, that, by prop••r ma|nagement, they might even mak•• Salt-Petre a staple commodity. The impurity of the Nitre I made was undoub••edly owing to the incompleteness of the putrefaction which proceeds to no great length in the curing of it; but if under such cir|cumstanc•••• eight ounces of stalks will ••ffo••d an ounce of im|pure Nitre, the•••• ••eems reason to believe that if the putri|f••ction were to 〈◊〉〈◊〉 completed in a bed of mould ti••l the To|bacco was r••duce•• to e••rth and proper substances mixed there|with during the progress of putrefacti••n to fix the 〈…〉〈…〉 Acid as it forms, a linivium drawn from such mould would yield a much larger quantity (with respect to the quantity of Tobacco) of much purer Nitre▪ and probably much more than any other su••stance known. Were I, therefore, a To|bacco Planter, I would certainly try wh••t might be done with a bed of m••uld m••de of refuse Tobacco, and doubt not but it would ••ully answer my expectations.