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sited oxyd of filver. In this cafe the folutionvery readily begins to cryftallize the moment itcools, and forms long needled cryftals, but atthe fame time a part of the fait is reduced, andthe mafs of cryftals and liquor is fouled with aquantity of black powder of reduced filver, whichhowever foon fubfides. The clear acetite whenkept in a bottle expofed to the light is alfo partlydecompofed, and the glafs foon becomes linedwith a brilliant filvery film. Acetite of filveris of ufe in chemical analyfis, particularly inexamining mixtures of the nitrats and muriats,where the operator wifhes to afcertain and fepa-rate the muriatic acid without adding any ex-traneous nitric acid, which would be the cafe ifthe nitrat of filver were employed.

When filver is treated with nitrous acid andalcohol, a white powder is depofited, which ful-minates with extreme violence, and which, fromthe analogy with the fulminating mercury pro-duced in the fame way, is probably an o'xalat offilver. e This preparation was difcovered byMr. Howard, in his attempts to communicateto other metals the fame fulminating propertywhich he had given to mercury, and is preparedin the fame manner as has been defcribed in thearticle Mercury.

Mr. Cruicklhank in repeating this experiment,diffolved 40 grains of filver in 2 ounces offtrong nitrous acid diluted with as much water,and on heating the folution with 2 ounces ofalcohol, he obtained 60 grains of a white powderwhich fulminated violently. Brugnatelli hasgiven the following method of preparing thelame. f Put 100 grains of lunar cauftic in aglafs, and pour on them firft an ounce of alcohol,and then as much concentrated nitrous acid.The mixture grows hot, boils, and an ether isvifibly formed, which flies off in vapour. Bydegrees the liquor becomes milky and is filledwith fmall white flocculi. When the liquorhas thickened by this precipitation, add colddiddled water to fufpend the ebullition, other-wife the precipitate would be re-diffolved, thencolIett the powder and dry it with a very mode-rate heat. This is the fulminating filver, andamounts to more than half the wqight of thelunar cauftic employed.

One grain placed on a lighted coal detonateswith a deafening report, if touched with the endof a glafs tube dipped in fulphuric acid, or withthe eledfric fpark, fo that in violence it greatlyexceeds the fulminating mercury.

The combination of oxyd of filver with am-jnonia is remarkable for affording the mod vio-

lently detonating fubftance yet known. Thiswas difcovered by Berthollet , and confideringthe multitude of experiments in which ammoniahas been employed along with the falts of filver,it is rather furprizing that it was not foonerdifcovered by fome ferious accident.

This fulminating ammoniacal oxyd is pre-pared in the following way, according to Ber-thollet the inventor, s and the diredtions givenby Dr.Higgins:* 1 difl'olve any quantity of filver,perfe&ly free from copper, in as little nitricacid, moderately dilute, as is fufficient, pour offthe clear folution from any black fediment which,may be left (and which is commonly gold) andadd to it lime water as long as any confiderableprecipitate falls down. Edulcorate this preci-pitate, which is a brown oxyd of filver, andthen lay it on feveral folds of filtering paper,or fpread it out on a fingle paper laid on afmooth dry lump of chalk, and dry the precipi-tate thoroughly in the open air. Set this oxydby for ufe in a well-corked phial. About i~oz. is obtained from an ounce of fine filver.The cauftic fixed alkalies may be ufed inlteadof the lime-water, but they do not adt with fomuch certainty. This oxyd diffolved in ammo-nia, forms the fulminating powder. For thispurpofe add 10 or 12 grains of this oxyd toabout half an ounce in meafure of liquid am-monia, perfectly cauftic and moderately dilute.This gives a fnapping noife, and blackens thewhole oxyd immediately, and diflolves either aportion of it only, leaving a black powder atthe bottom, or, if more ammonia is ufed, thewhole is difl'olved. Pour the clear folution offfrom the black powder, if any, and expofe itin a ftiallow veffel to the air. In ten or twelvehours a cryftalline pellicle appears,on the furfaceof the ammoniacal folution, which is the ful-minating filver, and is compofed of a congeriesof black filming cryftals. Take them out, whilftftill wet, and lay them in feparate parcels ofnot more than a grain or two on blotting paper,and let them dry in the air, carefully avoidingto touch them.

This fulminating powder has the followingproperties: even when ftill wet if it be preffedupon with a hammer or any hard body, it ful-minates with extreme violence, but when dry,the touch of a flender wire or even a feather,or a heat of about 96°, is fufficient to makeit explode. Even a moderate concuffion of theair is fufficient, fo that a heap may be explodedby the concuffion of any other in its imme-diate neighbourhood. Sometimes too it will

• Phil. Trans, for 1800. p, -8^,

1 Phil. Journ. 8vo. vol.vii. p. 185.h Higgins Miastcs, p. 324-

« Bfrthollet, Ann. Chcm. tom i-2 S

lyoi. u.