128 



CASTOROLOGIA. 



material was placed, and treated as follows: — A revolving fan, work- 

 ing at great speed, drove a current of air through the receiving box 

 and thence along an enclosed casing about a hundred feet in length. 

 The force of the air carried the mixed material from the receiving 

 box along the casing, but as the force of the draft diminished, the 

 power of gravitation took the work upon itself of separating every 

 fibre according to its weight, thus the heavy coarse hair and any 

 foreign substance mixed with it, fell soonest, and was gathered into 



THE HOOD, 

 OR BEAVER HAT IN ITS FIRST FORM. 



bins, while each succeeding grade of finer material was sorted and 

 deposited each with its kind, and practically divided, so as to show 

 every variety of quality contained in the original fleece. The finest 

 and most valuable fur was, owing to its lightness, blown to the ex- 

 treme edge of the casing, and freed from every impurity. 



This simple contrivance achieved what apparently is beyond the 

 appreciation of our most delicate mechanism, and this process 

 practically determined the consequent quality of the finished article, 

 as the next stages will show. Taking the grade of wool required 

 for the inside layer of the hat, to the " hat forming " machine, and 



