tbS Experimints on Ditonatton. 



VIII. 



An Account of Experiments defcrihed, and In part repeated, at the Sitting of the National In- 

 Jlitute of France, en the IJ/A Gtrmina/, in the Tear 4. By Citizens FOURCROT and 

 VaU^'ELIX ; On Detonations produced by ConciiJ/ion*. 



i HE energy and rapidity witli which the fupcr-oxigenated muriate of pot-adi inflames 

 and burns mod combuaiblc fubftances, is the fourcc from whicli the Citizens Fourcroy and 

 Vauquelin have derived the new fa(fls which they have communicated to the National In- 

 ftitute of France, and exhibited at the public fitting of tlie 15th Germinal, in the 4th year 

 of the Republic. Several chemifts had obferved, that this fait, difcovcred by Berthollet 

 about nine years ago, and which fcems to contain the elements and phenomena of thunder, 

 decrepitated and emitted fmall ele£lrical fparks by fri£lion,and fpontaneoully took fire with 

 fulphur. And an unfortunate experiment made in Oftober 1788, at Eflbne, had proved, 

 that when ground with fulphur and coal, to convert it into gunpowder, it takes fire fpon- 

 taneoully. Such were the firlk obfcrvations made .by Lavoifier, Pellelier and Van Mons, 

 when Citizens Fourcroy and Vauquelin undertook to examine the feries of e(Fe£ts of the 

 fiiper-oxigenated muriate of pot-afii on the feveral known combuflible bodies. The follow- 

 ing are the principal fafts which they have difcovered : 



1. Three parts of fuper-oxigenated muriate of -pot-afli, and one part of fulphur in pow- 

 der, triturated in a metallic mortar, caufed numerous and fuccelTive detonations to be 

 heard, refembling the cracks of a whip, the report of a piftol, or even that of mufquetry, 

 according to the rapidity of the motion, or force of preflurc applied. A few centigrams 

 (or fifth parts of a grain) of the fame mixture, ftruck brifkly with a hammer on an anvil, 

 exploded with a noife fimilar to that of a mulket, and torrents of purple light were feen 

 round ihe anvil. 1 he fame mixture thrown into concentrated fulphuric acid immediately 

 takes fire, and burns without noife with a white dazzling flame. 



2. Three parts of the fait, half a part of fulphur, and half a part of charcoal, alFord 

 flronger detonations than the foregoing, when triturated in the mortar, and a more confi- 

 derable noife when ftruck on the anvil. The flame of this mixture, when caufed to deto- 

 nate, or when thrown into the fulphuric acid, is more rapid, ftrong and red th?n that of 

 the preceding mixture. 



3. Equal parts of fuper-oxigenatcd muriate of pot-afh, and of antimony in powder, ful- 

 minate by the ftroke, and produce only reddilh fparks with the fulphuric acid. Zinc at a 

 light dofe alfo fulminates with a white flame, but fuffers no change by the fulphuric acid. 



4. Metallic arfenic detonates very ftrongly by the (Irokc of the hammer, and takes fire 

 with rapidity and extraordinary brilliancy by the contaft of fulphuric acid. In this laft 



fcrm, andcjeteris paribus in the dircfl fubiloplicstc ratio of their diameters. Atwood on Motion, SciS.V. Prop. 10. 

 And 3. The itiagnitudc, and perhaps denfity, of all chemical depofitions are affiftcd not only by the nature of 

 ihe ingrcdicikts and the <)uantity of folvcnt, but very much by the order of mixture and other circumftances of 

 manipulation. This laft obfervation fcrves to account for the various refults of thcfe and many other cxperimcntj 

 in which tranfparcncy, opacity, or colour, arc required to be produced. N. 

 • Annates de Chimie, XXL 135. 



experiment 



