Mr. W. Crum on a peculiar Fibre of Cotton. 335 



as well as great transparency. They are often broader, too, 

 than the usual fibre, and they show numerous folds, both lon- 

 gitudinal and transverse; but they are never twisted into the 

 corkscrew form of the ordinary fibre. 



It occurred to me that cotton of this description might be 

 detected among the wool as it is imported. I searched ac- 

 cordingly for any portions that had a different appearance 

 from the rest; and having collected and examined them, I 

 found one sort whose filaments had exactly the appearance 

 under the microscope of the coton mort in the pattern of M. 

 Koechlin. It occurs in the form of a small matted tuft of a 

 shining silky lustre, and usually contains in its centre the 

 fragment of a seed, or perhaps an abortive seed. It consists 

 of short fibres having litde tenacity. Specimens of it are 

 found in abundance among the motes or hard portions, called 

 droppings, rejected by the picking machine in the preparation 

 for spinning. Small tufts of it, however, do occasionally pass 

 the sifting process of the picking machine; and then, their 

 fibres being too short to be teazed out in the carding engine, 

 or drawn into threads in the subsequent operations of cotton 

 spinning, remain as minute lumps or knots upon the threads 

 of better wool. 



Although the microscopic appearance of the fibre in ques- 

 tion is that of a flat single blade, the cellular character of the 

 tissue scarcely admits of such a formation. We must rather 

 suppose that, like the healthy unripe cotton fibre, it was ori- 

 ginally an elongated cell or tube filled with liquid ; that the 

 seed around which it began to grow had died soon after its 

 formation, while the fibres which clothed it were yet soft and 

 pliable ; and that the flattening, and perhaps growing together 

 of the sides of the tube, was occasioned by the pressure from 

 the increasing crop of cotton attached to the numerous other 

 seeds confined in the same pod. 



To explain the bearing of this peculiar structure upon the 

 question whether cotton wool and colouring matters form 

 together a true chemical compound, or are held together by 

 a merely mechanical power, I must quote a passage from a 

 memoir on this subject which I read to the Philosophical 

 Society six years ago, and refer to the memoir itself for addi- 

 tional illustrations. 



" In many of the operations of dyeing and calico-printing, 

 the mineral basis of the colour is applied to the cotton in a 

 state of solution in a volatile acid. This solution is allowed 

 to dry upon the cloth, and in a short time the salt is decom- 

 posed, just as it woukl be, in similar circumstances, without 

 the intervention of cotton. During the decomposition of the 



