Nov. 1, 1864.] THE TECHNOLOGIST. 



ON CHEMISTRY APPLIED TO THE ARTS. 161 



stances, which in France bear the name of suint. The most interesting 

 fact connected with this is, that the 15 per cent, yielded by wool does 

 not contain, as shown by M. Chevreul, any salts of soda, but a large 

 quantity of salts of potash, the greatest part of which is combined with 

 an acid called sudoric ; and what increases the interest of this fact is, 

 that Messrs. Maumene and Rogelet displayed at the Exhibition of 1862 

 salts of potash which they had obtained commercially from this new 

 source. In fact, they have established in several of the large manufac- 

 turing centres of France, where considerable quantities of wool are 

 used, factories for the extraction of salts of potash from the suint, and 

 they supplied the jury with the following particulars : — That a fleece of 

 wool weighing 8 lbs. yielded on the average about l^lb. of dry suint, or 

 sudorate of potash, and this would further yield about seven ounces of 

 pure potash. If it is now considered that there is annually twenty mil- 

 lion pounds of wool washed in Rheims, thirty millions at Elbeuf, and 

 four millions at Fourmies, it would appear from this quantity that if it 

 were all subjected to Messrs. Maumen6 and Eogelet's treatment, about 

 two and a quarter million pounds of pure potash might be recoverable. 

 (For further details on this point, see Dr. Hofmann's Report on Chemical 

 Products and Processes in the last Exhibition.) Wool which has been 

 simply washed, as above described, is not sufficiently free from extra- 

 neous matters to be fit for application in manufactures. It is necessary 

 that it should be scoured, for which purpose, on the Continent, it ig 

 allowed to remain for some time in putrid urine, or weak ammo- 

 niacal liquor ; but in this country it is placed in strong alkaline of soap 

 or soft soap, passed through rollers to press out the excess of soap, 

 together with the impurities which it removes, well washed and dried. 

 In these operations wool loses in weight above 50 per cent, when of 

 good quality, and above 30 per cent, when inferior. But even then 

 the wool still retains a certain amount of fatty matters, which it yields 

 to hot alcohol. 



The following table, published by M. Chevreul, will give an idea of 

 the composition of wool (dried at 212°) : — 



Earthy matters 27-40 



Organic and inorganic salts, soluble in water (suint) 3274 



Fatty matters . _ 8-37 



Wool . 31-49 



100-00 



Elementary composition, C. 5066, H. 7-03, N. 17-74, O. 22-32, 

 S. 2-25. 



Before proceeding further, I would call attention to the curious fact 

 that the fatty matters of wool are completely different from the fatty 

 matters of the animal itself ; thus, whilst the ordinary suet will be 

 saponified by an alkali, the fat of the wool will not undergo that 



VOL. V. T 



