5 o THE SHEEP AND WOOL INDUSTRY 



On the other hand, if the cloth is a mixture of wool and 

 cotton, the cotton will remain undissolved. I have frequently 

 tested small pieces of tweed in this manner with the result 

 shown in the illustration. 



Over-scouring wool has a bad effect on the fibres. Over- 

 scouring is caused by having the liquor in the scouring tanks 

 too hot or too strong that is, liquor containing too much 

 caustic soap. Wool scoured in liquor like this gets washed 

 in an alkali bath which dissolves the extreme and delicate 

 edges of the fibres, thus injuring their felting properties and 

 making them brittle and harsh to the touch, which is a great 

 detriment to the wool when undergoing the combing and 

 spinning process, as it is inclined to fly, and a good number 

 of the fibres break when subjected to the tension necessary 

 in the production of some yarns. Any temperature over 

 230 F. will dissolve the oil contained in the medulla of 

 the wool fibres. It is necessary for all wools to retain this oil; 

 if not they lose a great deal of their elasticity and pliability. 

 Wool will resist most acids, though it can be destroyed by 

 immersion in a solution of very strong mineral acid. 



Cotton, linen, and other textile fibres of vegetable origin 

 will resist the action of caustic and alkali solutions, but they 

 are destroyed by the action of acids that wool will resist. 



Some manufacturers have an acid test made on each roll of 

 their cloth to prove that it contains no cotton or vegetable 

 fibres, as, if so, the acid would have eaten these out and 

 left a hole in the cloth. 



By immersing wool in a solution of sulphuric acid, strength 

 6 Twaddle, the temperature at 150 to 160 F., you can 

 destroy any vegetable matter in it without any great injury 

 to the wool fibres. This is how all the burrs, seeds, and 

 vegetable matter 'are removed from short wools, the acid 

 reducing them to a brittle state, so that if you got one of 

 the burrs and pressed it between two of your fingers it 

 would crumble into a fine dust. 



After leaving the acid bath the wool is artificially dried 



