Nov. 1, 1864.] 



THE TECHNOLOGIST. 



ON CHEMISTRY APPLIED TO THE ARTS. 15a 



meat has been salted, and thus to remove the salt, leaving the juice of 

 the meat available for use, while the salt is again in condition to be 

 employed as before. 



It will now be my agreeable duty to examine with you a few facts 

 relating to hair and wool. It is interesting to observe that hair, wool, 

 feathers, nails, and claws, may be all considered as promulgations of 

 the epidermis, and present nearly the same chemical composition, as 

 will be seen by the following table : — 





Is 



CO 



w 



"3 



to 



CO 



"a 



"cS 



'3 



2 o 



° ,2 



Carbon . . . 

 Hydrogen . . 

 Nitrogen . . 

 Oxygen and 

 Sulphur . . 



50-34 

 6-81 

 17-22 



2563 



50-89 

 6-78 

 17-25 



25-08 



51-09 



6-12 



16-91 



25-88 



50-14 



6-67 



17-94 



25-25 



52-43 



7-22 



17-93 



22-42 



50-40 



7-00 



16-70 



25-90 



53-60 



7-20 



16-30 



22-90 



100-00 



100-00 



100-00 



] oo-oo 



100-00 



100-00 



100-00 



These substances have also this peculiarity, that, notwithstanding their 

 great richness in organic matters, they are extremely slow to decompose. 

 Hair. — The only real point of interest connected with hair appears 

 to me to be the question as to what its various colours are to be ascribed, 

 and I regret that here I can only give conjectures and not positive facts. 

 Vauquelin and Fourcroy, who analysed hair most carefully half a 

 century ago, stated that hairs were hollow cylindrical tubes filled 

 with oils of various colour ; but Gmelin and others state that the 

 coloration of hairs is due to the different proportions of sulphur that they 

 contain. 



Quantity of Sulphur in Hair. 



Brown 4-98 



Black 4-85 



Red 5-02 



Grey . _ 4-03 



Recently Mr. Barreswil has published a paper, in which he states 

 that the coloration of hairs is probably due to the proportion of iron in 

 their composition ; and he argues that as iron is the essential element of 

 the colouring matter of blood, it is highly probable that it fulfils the 

 same office with respect to hair. I may state, en passant, that great 

 improvements have lately been made in dyeing human hair. Formerly 

 the patient had to undergo most unpleasant treatment, his head being 

 covered with a paste consisting of three parts of lime, and one of 

 litharge. An oil cap was then applied, and the patient left for twelve 



