6i 7 - 



XLV. 



Tannin industry. Hides. Leather. Trade in these products. 

 Other animal industries. 



GORDON PARKER. The principles of tanning. Journal of the So- 

 ciety of Chemical Industry, No. 15, August 15, 1910, p. 912-916. 

 London. 



Innumerable new methods have been proposed and patents have 

 been taken out during the last century for the acceleration and 

 improvement in tanning leather, mostly by those but remotely con- 

 nected with the trade. In spite of this the general outline in pro- 

 cess of tanning sole leather is much the same today as carried out 

 a thousand years ago. In short, the changes which have taken place 

 between the tanning sole leather even 1000 years ago and to-day 

 consist not so much in principle as in a more intelligent method 

 of carrying out the process. 



The raw material for the British tanner is the hide of oxen and 

 cows, and is drawn from practically all parts of the globe. From 

 the Argentine, Uruguay, China, and Africa, come hides which have 

 been dried in the sun ; from America, from all parts of Europe and 

 the Colonies, come hides in what is known as the salted condition : 

 the hides are piled, a sprinkling of salt between each, and gradually 

 the salt draws out the water, becomes dissolved, and diffuses in to 

 the interior. After lying in pile for some time, the excess water is 

 thrown off, arid the hides are resalted; in this condition they fre- 

 quently contain as much aa 30 per cent, of salt ou the original 

 weight of the hide. From the home market the hides are usually 

 obtained "green" or "fresh." The first process, therefore, is the 

 soaking and cleansing to soften the fibres, remove extraneous mat- 

 ters, salt, blood, dirt, etc., and to bring the hide back to its natural 

 state, In bygone days this was done by suspending the hides in 

 a running stream by the tanyard, but now the common custom is 

 to soak the hides in pits containing water. The hides are usually 

 given a change of one or two waters ; salted hides receive a longer 

 treatment and several changes of water until moderately free from 



