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table: des morceaux de boîtes furent lancés avec tant de rapidité qu'il y en eut qui passèrent au travers de deux planchers; d'autres firent sur la muraille des effets semblables a ceux des éclats de bombes.'-Chymie Expérimentale et Raisonnée tom. ii. p. 393.

"Had the alchemist proposed to fix water by the same apparatus, the nest of boxes must, I suppose, have likewise been ruptured; yet it does not follow that the explosion would have been so tremendous: indeed, it is probable that it would not, for if (as Mr. Kirwau remarked to me) substances which have the greatest specific gravity have likewise the greatest attraction of cohesion, the supposition that the vapour of water, would agree with a position of Sir Isaac Newton, that those particles recede from one another with the greatest force, and are most difficultly brought together, which upon contact cohere most strongly.

"Before I attempt to investigate the constituent principles of this powder, it will be proper to describe the process and manipulations which, from frequent trials, seem to be best calculated to produce it. 100 grains, or a greater proportional quantity of quicksilver, (not exceeding 500 grains), are to be dissolved, with heat, in a measured ounce and a half of nitric acid. This solution being poured cold upon two measured ounces of alcohol, previously introduced into any convenient glass vessel, a moderate heat is to be applied until an effervescence is excited. A white fume then begins to undulate on the surface of the liquor; and the powder will be gradually precipitated, upon the cessation of action and re-action. The precipitate is to be immediately collected on a filter, well washed with distilled water, and carefully dried in a heat not much exceeding that of a water bath. The immediate edulcoration of the powder is material, because it is liable to the reaction of nitric acid; and, whilst any of that acid adheres to it, it is very subject to the influence of light. Let it also be cautiously remembered, that the mercurial solution is to be poured upon the alcohol.

"I have recommended quicksilver to be used in preference to an oxyd, because it seems to answer equally, and is less expensive; otherwise, not only the pure red oxyd, but the red nitrous oxide, and turpeth, may be substituted; neither does it seem essential to attend to the precise specific gravity of the acid, or the alcohol. The rectified spirit of wine, and the nitrous acid of commerce, never failed with me, to pruduce a fulminating mercury. It is indeed true, that the powder prepared without attention is produced in different quantities, varieties in colour, and probably in strength. From analogy, I am disposed to think the whitest is the strongest; for it is well known that the black precipitates of mercury approach the nearest to the metallic state. The variation in quantity is remarkable; the smallest quantity I ever obtained from 100 grains of quicksilver being 120 grains, and the largest 132 grains. Much depends on very minute circumstances. The greatest product seems to be obtained when a vessel is used which condenses and causes most ether to return into the mother liquor; besides which, care is to be had in applying the requisite heat, that a speedy and not a violent action be effected. 100 grains of an oxide are not so productive as 100 grains of quicksilver.

"As to the colour, it seems to incline to black when the action of the acid of the alcohol is most violent, and vice versa.

"I need not observe, that the gasses which were generated during the combustion of the powder in the glass globe, were necessarily mixed with atmospheric air; the facility with which the electric fluid passes through a vacuum, made such a mixture nnavoidable.

"The cubical inch of gass received over water was not readily absorbed by it; and, as it soon extinguished a taper without becoming red, or or being itself inflamed, barytes water was let up to the three cubical inches received over mercury, when a carbonate of barytes was immediately precipitated.

"The residue of several explosions, after the carbonic acid had been separated, was found, by the test of nitrous gas, to contain nitrogen or azotic gas; which does not proceed from any decomposition of atmospheric air, because the powder may be made to explode under the exhausted receiver of an air pump. It is therefore manifest that the gasses generated during the combustion of the fulminating mercury, consist of carbonic acid and nitrogen gasses.

"The principal re-agents which decompose the mercurial powder are the nitric, the sulphuric, and the muriatic acids. The nitric changes the whole into nitrous gass, carbonic acid gass, acetous acid, and nitrate of mercury. I resolved it into these different principles, by distilling it pneumatically with nitric acid: this acid upon the application of heat soon dissolved the powder, and extricated a quantity of gass, which was found, by well-known tests, to be nitrous gass mixed with carbonic acid gass. The distillation was carried on until gass no longer came over. The liquor of the retort was then mixed with the liquor collected in the receiver, and the whole saturated with potass; which precipitated the mercury in a yellowish brown powder, nearly as it would have done from a solution of nitrate of mercury. This precipitate was separated by a filter, and the filtrated liquor evaporated to a dry salt, which was washed with alcohol. A portion of the salt being refused by this menstruum, it was separated by filtration, and recognized, by all its properties, to be nitrate of potass. The alcoholic liquor was likewise evaporated to a dry salt, which, upon the effusion of a little concentrate sulphuric acid, emitted acetous acid, contaminated with a feeble smell of nitrous acid, owing to the solubility of a small portion of the nitre in the alcohol.

"The sulphuric acid acts upon the powder in a remarkable manner, as has already been noticed. A very concentrate acid produced an explosion nearly at the instant of contact, on account, I presume, of the sudden and copious disengage ment of caloric from a portion of powder which is decomposed by the acid. An acid somewhat less concentrate likewise extricates a considerable quantity of caloric, with a good deal of gass; but, as it effects a complete decomposition, it causes no explosion. An acid diluted with an equal quantity of water, by the aid of a little heat, separates the gass so much less rapidly, that it may with safety be collected in a pneumatic apparatus. But, whatever be the density of the acid (provided no explosion be produced), there remains in the sulphuric liquor, after the separation of the gass, a white inflammable and uncrystallized powder mixed with some minute globules of quicksilver.

"To estimate the quantity, and observe the nature, of this uninflammable substance, I treated 100 grains of the fulminating mercury with sulphuric acid a little diluted. The gass being sepa

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Tated, I decanted off the liquor as it became clear, and freed the insoluble powder from acid by edulcoration with distilled water; after which I dried it, and found it weighed only 84 grains; consequently had lost 16 grains of its original weight. Suspecting, from the operation of the nitric acid in the former experiment, that these 84 grains (with the exception of the quicksilver globules) were oxalate of mercury, I digested them in uitrate of lime, and found my suspicion just. The mercury of the oxalate united to the nitric acid, and the oxalic acid to the lime. A new insoluble compound was formed; it weighed, when washed and dry, 48.5 grains. Carbonate of potass separated the lime, and formed oxalate of potass, capable of precipitating lime-water and muriate of lime; although it bad been depurated from excess of alkali, and from carbonate acid, by a previous addition of acetous acid. That the mercury of the oxalate in the 84 grains had united to the nitric aeid of the nitrate of lime was proved, by dropping muriatic acid into liquor from which the substance demonstrated to be oxalate of lime had separated; for a copious precipitation of calomel instantly ensued.

"The sulphuric liquor, decanted from the oxalate of mercury, was now added to that with which it was edulcorated, and the whole saturated with carbonate of potass. As effervescence ceased, a cloudiness and precipitation followed; and the precipitate being collected, washed and dried, weighed 3.4 grains: it appeared to be a carbonate of mercury. Upon evaporating a portion of the saturated sulphuric liquor, I found nothing but sulphate of potass: nor had it any metallic taste. There then remains, without allowing for the weight of the carbonic united to the 3.4 grains, a deficit from the 100 grains of mercuri. al powder of 12.6 grains, which I ascribe to the gass separated by the action of the sulphuric acid. To ascertain the quantity, and examine the nature of the gass so separated, I introduced into a very small tubulated retort 50 grains of the mercurial powder, and poured upon it three drachms, by measure, of sulphuric acid, with the assistance of a gentle heat. I first received it over quicksilver; the surface of which, during the operation, partially covered itself with a little black powder. "The gass, by different trials, amounted to from 28 to 31 cubical inches: it first appeared to be nothing but carbonic acid, as it precipitated barytes water, and extinguished a taper, without being itself inflamed, or becoming red. But upon letting up to it liquid caustic ammonia, there was a residue of from 5 to 7 inches of a peculiar inflammable gass, which burnt with a greenish-blue flame. When I made use of the water-tub, I obtained from the same materials from 25 to 27 inches only of gass, although the average quantity of the peculiar inflammable gass was likewise from 5 to 7 inches: therefore, the difference of the aggregate product, over the two fluids, must have arisen from the absorption, by the water, of a part of the carbonic acid in its nascent state. The variation of the quantity of the inflammable gass, when powder from the same parcel is used, seems to depend upon the acid being a little more or less dilute. "With respect to the nature of the peculiar inflammable gass, it is plain to me, from the reasons I shall immediately adduce, that it is no other than the gass (in a pure state) into which the nitrous etherized gass can be resolved, by treatment with dilute sulphuric acid.

"The Dutch chemists have shewn, that the nirous etherized gass can be resolved into nitrous gass, by exposure to concentrate sulphuric acid, and that, by using a dilute instead of a concentrate acid, a gass is obtained which enlarges the flame of a burning taper, so much like the gasseous oxide of azote, that they mistook it for that substance, until they discovered that it was permanent over water, refused to detonate with hydrogen, and that the fallacious appearance was owing to a mixture of nitrous gass with inflammable gass.

"The inflammable gass separated from the powder, answers to the description of the gass which at first deceived the Dutch chemists: 1st, in being permanent over water; 2dly, refusing to detonate with hydrogen; and, 3dly, having the appearance of the gasseous oxide of azote, when mixed with nitrons gass.

"The gass separable by the same acid, from nitrous etherized gass, and from the mercurial_powder, have therefore the same properties. Every chemist would thence conclude, that the nitrous etherized gass is a constituent part of the powder, and the inflammable aud nitrous gass, instead of the inflammable and carbonic acid gass, had been the mixed product extricated from it by dilute sulphuric acid.

"It however appears to me, that nitrous gass was really produced by the action of the dilute sulphuric acid; and that, when produced, it united to an excess of oxygen present in the oxalate of mercury.

"To explain how this change might happen, I must premise, that my experiments have shewn me that oxalate of mercury can exist in two, if not in three states. 1st. By the discovery of Mr. Ameilon, the precipitate obtained by oxalic acid, from nitrate of mercury, fuses with a hissing noise. The precipitate is an oxalate of mercury, seemingly with excess of oxygen. Mercury dissolved in sulphuric acid and precipitated by oxalic acid, and also the pure red oxide of mercury digested with oxalic acid, give oxalates in the same state. 2dly. Acetate of mercury, precipitated by oxalic acid, although a true oxalate is formed, has no kind of inflammability. I consider it as an oxalate with less oxygen than those above-mentioned. 3dly. A solution of nitrate of mercury, boiled with dulcified spirit of nitre, gives an oxalate more inflammable than any other; perhaps it contains most oxygen.

"The oxalate of mercury remaining from the powder in the sulphuric liquor is not only always in the same state as that precipitated from acetate of mercury, entirely devoid of inflammability, but contains globules of quicksilver, consequently it must have parted with even more than its excess of oxygen; and if nitrous gass was present, it would of course seize at least a portion of that oxygen. It is true, that globules of quicksilver may seem incompatible with nitrous acid; but the quantity of the one may not correspond with that of the other, or the dilution of the acid may destroy its action.

"As to the presence of the carbonic acid, it must have arisen either from a complete decomposition of a part of the oxalate; or admitting the nitrous etherized gass to be a constituent principle of the powder, from a portion of the oxygen, not taken up by the nitrous gass, being united with the carbon of the etherized gass.

"The muriatic acid, digested with the merca

Of oxalate and mercury And a deficit, to be ascribed to the nitrous etherized gass and excess of oxygen,

86 grains.

14

100

"It may perhaps be proper to proceed still further, and recur to the 48.5 grains, separated by nitrate of lime from the 84 grains of mercurial oxalate and globules of quicksilver. These 48.5 grains were proved to be oxalate of lime; but they contained a minute inseparable quantity of mercury, almost in the state of quicksilver, formerly part of the 84 grains from which they were separated. Had the 48.5 grains been pure calcareous oxalate, the quantity of pure oxalic acid in them would, according to Bergmann, be 23.28 grains. Hence, by omitting the two grains of mercury, in the 3.4 grains of carbonate, 100 grains of the mercurial powder might have been said to contain of pure oxalic acid 23.28 grains; of mercury 62.72 grains; and of nitrous etherized gass and excess of oxygen 14 grains. But as the 48.5 grains were not pure oxalate, inasmuch as they contained the mercury they received from the 84 grains, from which they were generated by the mitrate of lime, some allowance must be made for the mercury successively intermixed with the $4 grains and the 48.5 grains. In order to make corresponding numbers, and allow for unavoidable errors, I shall estimate the quantity of that mercury to have amounted to two grains, which I must of course deduct from the 35.28 grains of oxalic acid. I shall then have the following statement: That 100 grains of fulminating mercury ought to contain of pure oxalic acid, Of mercury formerly united to the oxalic acid, Of mercury dissolved in the sulphuric liquor,

And of mercury left in the sulphuric liquor, after the separation of the gasses,

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60.72

Of nitrous etherized gass, and Total of mercury, excess of oxygen,

21.28 grains.

64.72

14

100

rial powder, dissolves a portion of it, without extricating any notable quantity of gass. The dissoIation evaporated to a dry salt tastes like the corrosive sublimate; and the portion which the acid does not take up is left in a state of an inflammable oxalate.

"These effects all tend to establish the existence of the nitrous etherized gas, as a constituent part of the powder; and likewise corroborate the explanation 1 have ventured to give of the action of the sulphuric acid. Moreover, a measured ounce and a half of nitrous acid, holding 100 grains of mercury in solution and two measured ounces of alcohol, yield 90 cubical inches only of gass: whereas, without the intervention of mercury, they yield 210 inches. Upon the whole, I trust it will be thought reasonable to conclude, that the mercurial powder is composed of the nitrous etherized gass, and of oxalate of mercury with excess of oxyen. 1st. Because the nitric converts the mercurial powder entirely into nitrous gass, carbonic acid gass, acetous acid, and nitrate of mercury. 2dly. Because the dilute sulphuric acid resolves it into an unintiaminable oxalate of mercury, and separates from it a gass resembling that into which the same acid resolves the nitrous etherized gass. 3dly. Because an uninflammable oxalate is likewise left, after the muriatic acid has converted a part of it into sublimate. 4thly. Because it cannot be formed by boiling nitrate of mercury in dulcified spirits of nitre; although a very inflammable oxalate is by this means produced. 5thly. Because the difference of the product of gass, from the same measures of alcohol and nitrous acid, with and without mercury in solution, is not trifling; and, 6thly. Because nitrogen gass was generated during its combustion in the glass globe.

"Should my conclusions be thought warranted by the reasons I have adduced, the theory of the combustion of the mercurial powder will be obvious to every chemist. The hydrogen of the oxalic acid, and of the etherized gass, is first united to the oxygen of the oxalate, forming water; the carbon is saturated with oxygen, forming carbonic acid gass; and a part, if not the whole of the nitrogen of the etherized gass, is separated in the state of nitrogen gass; both which last gasses, it may be recollected, were after the explosion present in the glass globe. The mercury is revived, and, I presume, thrown into vapour; as may well be imagined, from the immense quantity of caloric extricated, by adding concentrate sulphuric acid to the mercurial powder.

"I will not venture to state with accuracy in what proportions its constituent principles are combined. The affinities I have brought into play are complicated, and the constitution of the substances I have to deal with not fully known. But to make round numbers, I will resume the statement, that 100 grains of the mercurial powder lost 16 grains of its original weight, by treatment with dilute sulphuric acid: 84 grains of the mercurial oxalate, mixed with a few minute globules of quicksilver, remained undissolved in the acid. The sulphuric liquor was saturated with carbonic of potass, and yielded 3.4 grains of carbonate of mercury. If 1.4 grains should be thought a proper allowance for the weight of carbonic acid in the 3.4 grains, I will make that deduction, and add the remaining two grains to the 84 grains of mercurial oxalate and quicksilver; I shall then have,

"Since 100 grains of the powder seem to contain 64.72 grains of mercury, it will be immediately enquired, what becomes of 100 grains of quicksilver, when treated as directed, in the description of the process for preparing the fulminating mercury.

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It has been stated that 100 grains of quicksilver produce, under different circumstances, from 120 to 132 grains of mercurial powder; and, if 100 grains of this powder contain 64.72 grains, 120 grains, or 132 grains, must, by parity of reasoning, contain 78.06 grains, or 85.47 grains; therefore 13.34 grains, or 20.75 grains, more of the 100 grains are immediately accounted for; because 63.72 grains + 13.34 grains 78.06, and 64.72 grains + 20.75 grains = 85.47 grains. The remaining deficiency of 21.94 grains, or 14.53 grains, which, with the 78.06 grains, or 85.47 grains, would complete the original 100 of quicksilver, remains partly in the liquor from which the pow der is separated, and is partly volatilized in the white dense fumes, which in the beginning of this paper I compared to the liquor fumans of Liba

vius. The mercury cannot, in either instance, be obtained in a form immediately indicative of its quantity; and a series of experiments, to ascertain the quantities in which many different substances can combine with mercury, is not my present object. After observing that the mercury left in the residuary liquor can be precipitated in a very subtle dark powder, by carbonate of potass, I shall content myself with examining the nature of the white fumes.

"It is clear that these white fumes contain mercury: they may be wholly condensed in a range of Wolfe's apparatus, charged with a solution of muriate of ammonia. When the operation is over, a white powder is seen floating with ether on the saline liquor, which, if the bottles are agitated, is entirely dissolved. After the mixture has been boiled, or for some time exposed to the atmosphere, it yields to caustic ammonia a precipi. tate, in all respects similar to that which is sepa. rated by caustic ammonia from corrosive sublimate.

"I would infer from these facts, that the white dense fumes consist of mercury, or perhaps oxide of mercury, united to the nitrous etherized gass; and that, when the muriate of ammonia containing them is exposed to the atmosphere, or is boiled, the gass separates from the mercury; and the excess of nitrous acid, which always comes over with nitrous ether, decomposes the ammoniacal muriate of sublimate, and forms corrosive mercurial muriate or sublimate. This theory is corroborated by comparing the quantity of gass estimated to be contained in the fulminating mercury with the quantities of gass yielded from alcohol and nitrous acid, with and without mercury in solution; not to mention that more ether, as well as more gass, is produced without the intervention of mercury; and that, according to the Dutch chemists, the product of ether is always in the inverse ratio to the product of nitrous etherized gass. Should a further proof be thought necessary to the existence of the nitrous etherized gass in the fulminating mercury, as well as in the white dense fumes, it may be added, that if a mixture of alcohol and nitrous acid holding mercury in solution be so dilute, and exposed of a temperature so low that neither ether nor nitrous etherized gass are produced, the fulminating mercury, or the white fumes, will never be generated; for, under such circumstances, the mercury is precipitated chiefly in the state of an inflammable oxalate. Further, when we consider the different substadces formed by an union of nitrous acid and alcohol, we are so far acquainted with all, except the ether and the nitrous etherized gass, as to create a presumption, that no others are capable of volatilizing mercury, at the very low temperature in which the white fumes exist, since, during some minutes, they are permanent over water of 40° Fahrenheit.

"Hitherto, as much only has been said of the gass which is separated from the mercurial powder by dilute sulphuric acid, as was necessary to identify it with that into which the same acid can resolve the nitrous etherized gass: 1 have further to Speak of its peculiarity.

"The characteristic properties of the inflammable gass seem to me to be the following: 1st. It does not diminish in volume, either with oxygen or nitrous gass. 2dly. It will not explode with oxygen by the electric shock, in a close vessel. 3dly. It burns like hydrocarbonate, but with a blueish-green Rame; and, 4thly. It is permanent over water.

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"It is of course either not formed, or is convertible into nitrous gas by the concentrate nitric and muriatic acids; because by those acids, no inflammable gass was extricated from the powder. "Should this inflammable gass prove not to be hydrocarbonate, I shall be disposed to conclude that it has nitrogen for its basis; indeed, I am at this moment inclined to that opinion, because I find that Dr. Priestley, during his experiments on his dephlogistigated nitrous air, once produced a gass which seems to have resembled this inflammable gass, both in the mode of burning and in the colour of the flame.

"After the termination of the common solution of iron in spirit of nitre, he used heat, and got, says he, such a kind of air as I had brought nitrous air to be, by exposing it to iron, or liver of sulphur; for, on the first trial, a candle burned in it with a much enlarged flame. At another time, the application of a candle to air produced in this manner was attended with a real, though not a loud explosion; and immediately after this a greenish-coloured flame descended from the top to the bottom of the vessel in which the air was contained. In the next produce of air, from the same process, the flame descended blue, and very rapidly from the top to the bottom of the vessel.

"These greenish and blue-coloured flames, descending from the top to the bottom of the vessel, are precisely descriptive of the inflammable gass separated from the powder. If it can be produced with certainty by the repetition of Dr. Priestley's experiments, or should it by any means be got pure from the nitrous etherized gass, my curiosity will excite me to make it the object of future research; otherwise, I must confess, I shall feel more disposed to prosecute other chemical subjects: for having reason to think that the density of the acid made a variation in the product of this gass, and having never found that any acid, however dense, produced an immediate explosion, I once poured six drachms of concentrate acid upon 50 grains of the powder. An explosion, nearly at the instant of contact, was effected: I was wounded severely, and most of my apparatus destroyed. A quantity moreover of the gass I had previously prepared was lost by the inadvertency of a person who went into my laboratory, whilst I was confined by the consequences of this discouraging accident. But should any one be desirous of giving the gass a further examination, I again repeat, that as far as I am enabled to judge, it may with safety be prepared by pouring three drachms of sulphuric acid, diluted with the same quantity of water, upon 50 grains of the powder, and then applying the flame of a candle until gass begins to be extricated. The only attempt I have made to decompose it, was by exposing it to copper and ammonia; which during several weeks did not effect the least alteration.

"I will now conclude (says Mr. Howard), by observing, that the fulminating mercury seems to be characterised by the following properties :

"It takes fire at the temperature of S68 Fahrenheit; it explodes by friction, by flint and steel, and by being thrown into concentrate sulphuric acid. It is equally inflammable under the exhausted receiver of an air-pump, as surrounded by atinospheric air; and it detonates loudly, both by the blow of a hammer, and by a strong electrical shock.

"Notwithstanding the compositions of fulminat. ing silver and of fulminating gold differ essentially

from that of fulminating mercury, all three have similar qualities. In tremendous effects, silver undoubtedly stands first, and gold perhaps the last. The effects of the mercurial powder and of gunpowder admit of little comparison. The one exerts, within certain limits, an almost inconceivable force: its agents seem to be gass and caloric, very suddenly set at liberty, and both mercury and water thrown into vapour. The other displays a more extended but inferior power: gass and caloric are, comparatively speaking, liberated by degrees; and water, according to count Rumford, is thrown into vapour.

"Hence it seems that the fulminating mercury, from the limitation of its sphere of action, can sel. dom, if ever, be applied to mining; and, from the immensity of its initial force, cannot be used in fire-arms, unless in cases where it becomes an object to destroy them; and where it is the practice to spike cannon, it may be of service, because I apprehend it may be used in such a manner as to burst cannon without dispersing any splinters, "The inflammation of fulminating mercury by concussion offers nothing more novel or remarkable than the inflammation, by concussion, of many other substances. The theory of such inflammations has been long since exposed by the celebrated Mr. Berthollet, and confirmed by Messieurs Fourcroy and Vauquelin: yet, I must confess, I am at a loss to understand why a small quantity of mercurial powder made to detonate by the hammer or the electric shock, should produce a report so much louder than when it is inflamed by a match, or by flint and steel. It might at first be imagined, that the loudness of the report could be accounted for, by supposing the instant of the inflammation, and that of the powder's confinement between the hammer and anvil, to be precisely the same; but, when the electrical shock is sent through or over a few grains of the powder, merely laid on ivory, and a loud report in consequence, I can form no idea of what causes such a report.

"The operation by which the powder is prepared, is perhaps one of the most beautiful and surprising in chemistry; and it is not a little interesting to consider the affinities which are brought into play. The superabundant nitrous acid of the mercurial solution must first act on the alcohol, and generate ether, nitrous etherized gas, and oxalic acid. The mercury unites to the two last in their nascent state, and relinquishes fresh nitrous acid, to act upon unaltered alcohol. The oxalic acid, a predisposing affinity seems exerted in favour of its quantity, is evidently not formed fast enough to retain all the mercury; otherwise, no white fumes during a considerable period of the operation, but fulminating mercury alone will be produced.

"Should any doubt still be entertained of the existence of the affinities which have been called predisposing or conspiring, a proof that such affinities really exist will, I think, be afforded, by comparing the quantity of oxalic acid which can be generated from given measures of nitrous acid and alcohol, with the intervention of mercury, and the intervention of other metals. For instance, when two measured ounces of alcohol are treated with a solution of 100 grains of nickel in a measured ounce and a half of nitrous acid, little or no precipitate is produced; yet, by the addition of oxalic acid to the residuary liquor, a quantity of oxalate of nickel, after some repose, is deposited. Copper affords another illustration; 100 grains of

copper dissolved in a measured ounce and a half of nitrous acid, and treated with alcohol, yielded me about 18 grains of oxalate, although cupreous oxalate was plentifully generated by dropping oxalic acid into the residuary liquor. About 21 grains of pure oxalic acid seem to be produced from the same materials, when 100 grains of mercury are interposed. Besides, according to the Dutch paper, more than once referred to, acetous acid is the principal residue after the preparation of nitrous ether. How can we explain the formation of a greater quantity of oxalic acid from the same materials, with the intervention of 100 grains of mercury, than with the intervention of 100 grains of copper, otherwise than by the notion of conspiring affinities, so analagous to what we see in other phænomena of nature?

"I have attempted, without success, to communicate fulminating properties, by means of alcohol, to gold, platina, antimony, tin, copper, iron, lead, zinc, nickel, bismuth, cobalt, arsenic, and manganese; but I have not yet sufficiently varied my experiments to enable me to speak with absolute certainty. Silver, when 20 grains of it were treated with nearly the same proportions of nitrous acid and alcohol as 100 grains of mercury, yielded, at the end of the operation, about three grains of a grey precipitate, which fulminated with extreme violence. Mr. Cruickshank had the goodness to repeat the experiment: he dissolved 40 grains of silver in two ounces of the strongest nitrous acid, diluted with an equal quantity of water, and obtained (by means of two ounces of alcohol) 60) grains of a very white powder, which fulminated like the grey precipitate above described. It probably combines with the same principles as the mercury, and of course differs from Mr. Berthollet's fulminating silver, before alluded to. I observe, that a white precipitate is always produced in the first instance; and that it may be preserved by adding water as soon as it is formed; otherwise, when the mother liquor is abundant, it often becomes grey, and is re-dissolved."

Several trials of the mercurial powder were afterwards made at Woolwich in conjunction with colonel Bloomfield and Mr. Cruickshank, upon heavy guns, carronades, &c. from which Mr. Howard generally infers, that any piece of ordnance might be destroyed, by employing a quantity of the mercurial powder equal in weight to one half of the service-charge of gunpowder; and, from the seventh and last experiment, we may also conclude that it would be possible so to proportion the charge of mercurial powder to the size of different cannons, as to burst them without dispers ing any splinters. But the great danger attending the use of fulminating mercury, on account of the facility with which it explodes, will probably prevent its being employed for that purpose.

"In addition to the other singular properties of the fulminating mercury (says Mr. Howard), it may be observed, that two ounces inflamed in the open air seem to produce a report much louder than when the same quantity is exploded in a gun capable of resisting its action. Mr. Cruickshank, who mode some of the powder by my process, remarked that it would not inflame gunpow der. In consequence of which, we spread a mixture of coarse and fine-grained gunpowder upon a parcel of the mercurial powder; and after the inflammation of the latter, we collected most, if not all, of the grains of gunpowder. Can this extraordinary fact be explained by the rapidity of

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