360 ON ARTIFICIAL TANNIN. 



unnessary to trespass on the time of the Society by stating 

 these experiments, conceiving those I have stated to be suffi- 

 cient to show, that any given quantity of vegetable matter 

 can generally be employed, io its recent and organized state, 

 with much more advantage than when it has been decom- 

 posed, and no inconsiderable part of its component parts 

 has been dissipated and lost, during the progress of the pu- 

 trefactive fermentation. 



X. 



Abstract of a Paper on the tanning Substances formed by 

 the Action of Nitric Acid on several vegetable Matters : 

 by Mr. Chevreul *. 



Mr. Hatchett's i.MR. HATCHETT has distinguished three varieties of 

 artificial tanning matter produced, 1st, by the action of 

 nitric acid on any vegetable, animal, or mineral carbona- 

 ceous substance : 2d, by its action on common resin, indi- 

 go, dragon's blood, &c. + : 3d, by the action of sulphuric 

 acid on camphor, common resin, elemi, &c. 



2. In the present paper I shall speak only of the first two 

 varieties of tanning matter, reserving the third for a sepa. 

 rate paper. 



Part I. Tanning matter formed with resinous sub* 

 stances. 



§ I. With Indigo. 



Prepared from 3. This is what I mentioned in my former paper, under 



Indigo. ^ e name f a substance of an oily appearance ;£." It was of 



_ b j an orange red colour, fluid at a temperature of 15°. 



[59° F,.]j but growing thick in the air: it had an acid, 



* Ann. de Chim. Vol. LXXIII, p. 36. Read to the Institute, 

 July, 1809. 



•f Mr. Hatchett having observed, that the most carbonaceous 

 substances were best adapted for conversion into tanning matter, 

 supposed, that, when this matter was formed from resins, these lost 

 a part of their hidrogen, and were thus made to approximate 

 carbonaceous substances. 



| See Journal, vol. xxx, p. 353. 



astringent, 



