FOR SCOURING WOOL. 5 



the wool will rapidly disappear : the hotter the water, the 

 more quickly it will melt." 



This melting of wool is, indeed, an instructive experiment, 

 and is of sufficient character to be shown, even upon the plat- 

 form. It will require two or three minutes only, and I have 

 prepared it for your instruction. 



I have here an alkaline solution of twenty degrees Baume. 

 This little instrument measures the specific gravity of liquids, 

 and is the common way of testing their strength. The alkali 

 stands at twenty, Baume, its temperature is 170, quite a little 

 less than boiling. Water at this temperature is rather hot to 

 hold one's hands in, but is not hot enough to really scald 

 them. Into this liquid I drop a quantity of wool. In a 

 short time the wool will be dissolved. Three minutes have 

 sufficed in previous experiments, and I think it will be time 

 enough in this instance. The wool disappears in the liquid, 

 just as sugar does in your coffee. I pour this mixture 

 through a glass funnel you see that there are no lumps of 

 wool in it. I pass it through a cold metal strainer, an opera- 

 tion that will show what has been done. The meshes have 

 caught a white substance, which is a soap of wool. All fibre, 

 or fibrous appearance, has disappeared. 



The experiment is by no means a new one. Elwell, in his 

 modern chemistry, published in 1806, speaks of a process 

 which Chaptal had lately invented, whereby wool, instead of 

 oil, was to be combined with an alkali to produce soap. The 

 object was probably commercial manufacture of soap. 



Now, in order to economize time, I have dissolved the 

 wool in strong alkali. Other experiments, made especially for 

 this occasion, give the following results : 



20 degrees 3 minutes. 



15 " 3 minutes. 



10 " 5 minutes. 



5 " 25 minutes. 



In these experiments there has been a considerable amount 

 of instruction in other departments than the dissolving of 

 wool. We tried some goods which were bought for all wool, 

 and so warranted. It was astonishing how much material 

 there was left after we had dissolved out all the wool, and it 

 would not be surprising if, after all, some cotton had crept 

 by mistake into these all-wool goods. At all events, it acted 

 under the burning test exactly the same as cotton. 



Now, in the washing of woolen fabrics, you can all apply 

 the experiment \\ithout difficulty. I do not mean to insinuate 



