AKTIFICIAL TAN. 23 



V. 



Second Communication on Artificial Tan. By Charles 

 Hatchett, Efq. Abridged from the Philofophical Tranf- 

 adtionsfor 1805. 



§1. 



1 HE artificial tan *, procured as defcribed in the firft com- Name of thear- 

 inunication (fee our Vol. XI I. p. ?/21), had been named tan- Jlf^ftancg"^."^ 

 nin by Mr. Hatchett ; but the ohjeclion having being made to terid, 

 this, that tannin was deftroyed by the nitric acid, while the 

 artificial tanning fubftance was aQually formed by it, induced 

 Mr. Hatchett to expunge the word tannin wherever it had 

 been applied to the latter. It alfo induced the author to 

 ftiake the following experiments on the comparative effeSs 

 produced by nitric acid on thofe fubftances which contain 

 moft tannin, and alfo feme others in which a tanning fub- 

 (lance has been produced, under circumftances in fome re- 

 ipedis different from thofe defcribed. 



Although it is not abfolutely aflerted ihat the tanning fub- 

 flance is indeftrudible by nitric acid, yet the following expe- 

 riments prove, that to produce this efFe6l muft at leaft be the 

 work of much time and difficulty. 



1. Twenty grains of the artificial tan were diflTolved in half Experiments to 

 an ounce of ftrong nitric acid, of the degree of 1.40 ; the fo- P''°^^!''^^ '^^^ 

 lution diftilled till (he whole of the acid came over, which nearly indeftnicj 

 acid was returned back on the retiduum, and the diftillation *''?'^ ^y ^^^'^'^ 

 repeated three times in this manner. Care was taken not to 

 overheat the refuluum ; and then, when examined, did not 

 appear to have fufFered any alteration in its properties, 



* In feveral parts of the abridgement of Mr. Hatchett's papers, 

 the artificial tanning fubftance has been called the new tan and arti~ 

 ficial tatty and tanning matter tan., for the fake of brevity. It was 

 thought neceflary to mention this, as the name tan is ufually ap- 

 propriated to oak bark in a certain ftate ; which, with fnigular im- 

 propriety, is that in which it contrains lealt tanning matter, after 

 having been ufed in the tanners' pits, — Abr. 



2. Ten 



