190 Cheniijlry. 



the place of thofe burnt awav. Tt is fin^xilnr that no oxictc of 

 refidue of anv kind could be dilcovcrcd ; and it is probable 

 that the gold was \o'aiiliztd by the fame heat that occafioned 

 its deflagration : this ))oint, however, is to lie further invef- 

 tigated, when a laroer portion of gold will be cx|)ofed to the 

 artioii of the Voltaic circuit, to determine with certainty 

 ■whether the whole, or anv part of it, is converted into vapour, 

 in our number for September, we mentioned the conibuf- 

 tion of phof|)horus by the Voltaic trougli, which was effected 

 bv putting a fmall piece on the point of an iron wire, and 

 deflaoraiiiiq; tlie wire bv brinorins; it in contaft in the circuit. 

 By fnnilar means the Society exploded gunpowder. A fniau 

 portion of it was dii'pofed in the folds of foaie gold leaf, which 

 was then deflagrated in the manner already defcribed, and 

 inflamed the powder. 



CHRMI3TRV. 



A new faft was mentioned at a late meeting of the Britifli 

 Mineralogical Society, by Mr. Sandman, one of the mem- 

 bers, and an excellent chemirt. Some months fince, to one 

 part of butter of antimony he added five parts of water : in- 

 ftead of an inftant precipitation takin;j; place, the mixture af- 

 fumed the form of a thickifh mafs, of fuch a confiltency, that 

 it would not even pour from the vcfTcI. After four months, 

 the mixture began to clear itfclf, and threw down a ouantity 

 of very white ihiall cryllals, fome of which were laid before 

 the Society. Their form could not be accurately determined, 

 but fecmed to approach the cubic. Whether they be a cryf- 

 lallizcd oxide, or merely a muriate of antimony, has not yet 

 been afcertained ; but the queftion is to be invedigated, and 

 the experiment will be repeated on a large fcalc. 



The ingenious Mr. Davy, of the Royal Inliitution of Great 

 Britain, has been occupied for fome time in a fcries of expe- 

 riments upon tanning, which will foon be laid before the 

 public. He has tried a number of woods and barks, bcfides 

 thofe that have been hitherto tbought exclufively adapted to 

 the purpofe, and has met with feveral that contain the tan- 

 ning principle in great quantity. His experiments will lead 

 to a great faving in the expcnfe of even oak bark, which it 

 has been ufual to have picked and feparated from one part of 

 the rind, which is found to be, notwithllanding, as rich in 

 tan as any other part of the bark. One circumllance re- 

 marked by this chemift is curious : Acorns do not feem to 

 ■contain in their natural ftate any portion of tan; but after 

 being baked in a jieat of about aia'^ F. they are found 

 to contain a conficierable quantity. If they be overbakedj 

 they again lofc that quality. 



The 



