THE TECHNOLOGIST. [Dec. I, 1864. 



198 ON CHEMISTRY APPLIED TO THE ARTS. 



so would be to undertake far too wide a field of research. All that I 

 can attempt in this lecture is to give an idea of their composition, and 

 to describe some of their most recent applications to arts and manufac- 

 tures. 



The question of the source of the fatty matters in herbivorous 

 animals has been the subject of a great number of scientific researches, 

 but those of Baron Liebig, Dumas, Boussingault, Payen, and Mine 

 Edwards, have left no doubt that when the food of an animal contains 

 a sufficient amount of fatty matter, this is simply extracted from the 

 food, and stored or consumed according to the animal's habits — that is to 

 say, its consumption is in ratio to the activity of the animal ; thus, an 

 animal in a state of great activity is comparatively thin, but Avhen 

 confined in a pen or stall it quickly fattens. These gentlemen also 

 proved that when the food is deficient in fatty matters a portion of the 

 amylaceous or saccharine matter becomes converted into fatty matter. 

 The most decisive experiments on this head were made by Mr. Milne 

 Edwards, who found that when bees were confined under a glass shade 

 with no food but honey, they converted the greater portion of it into 

 wax. Notwithstanding these proofs, however, chemists found it diffi- 

 cult to understand how substances so rich in oxygen as amylaceous ones 

 became converted into a class of matters containing so little of that 

 element, but Baron Liebig has recently published a paper which has 

 partially solved this problem, showing that animals give off, during 

 respiration, a larger amount of oxygen than is contained in the air 

 Inspired, which excess must be derived from certain organic substances 

 circulating in the blood. Fatty matters may be classed under two 

 heads, viz., vegetable and animal. The first are generally composed of a 

 solid, called margarine, and a liquid, called oleine. The latter generally 

 contains three substances, viz., two solids, stearine and margarine, and 

 one liquid, oleine. I say generally, because there are exceptions ; thus 

 in palm-oil palmetine is found, in linseed oil linoleine, in sperm oil 

 spermaceti, and in waxes several peculiar acids. Let us now examine 

 the composition of some of the most abundant fatty matters found in 

 animals. The knowledge of the composition of these substances — of 

 suet, for example — was most unsatisfactory until 1811, when my learned 

 and eminent master, M. Chevreul, published his elaborate researches, 

 by which he demonstrated the real composition of fatty matters in 

 general, and that they might be considered as real organic salts. Thus 

 suet is composed of stearic, margaric, and oleic acids combined with the 

 oxide of glyceryle. The three above-named acids he showed to be com- 

 posed as follows : — 





Stearic 



Margaric 



Oleic 





acid. 



acid. 



acid. 



Carbon 



... 68 



34 



36 



Hydrogen 



... 66 



33 



33 



Oxygen 



5 



3 



3 



Water 



... 2 



1 



1 



