Pr. BoUey on the Theory of Dyeing. 495 



resisted the action of the well-prepared reagent so completely, 

 that it did not even SM'ell up under its influence." I shall have 

 to notice directly, that not a single sample of cotton prepared 

 with mordant and dyed in a dye-house, withstood the action 

 of the reagent. Induced by Schlossberger's statement, I laid 

 flock-cotton in various salt solutions (common salt, sal-ammoniac, 

 phosphate of soda, nitrate of soda, chloride of barium, &c.), 

 boiled it therein, removed it, dried it between blotting-paper 

 without wasliing, and placed it under the microscope in cuprate 

 of ammonia. In every case it was dissolved. It may, indeed, 

 be true that the addition of certain salts to the reagent weakens 

 or entirely destroys its action ; and if the cotton fibre submitted 

 by Schlossberger to the action of the cuprate of anmionia was 

 still wet with the salt solution, the effect might have been the 

 same as the addition of a certain amount of such solution ; but 

 fibres merely steeped are always dissolved. 



The appearance presented by the dyed cotton under these cir- 

 cumstances is the same in the case of nearly all colours. 



The cotton, after twisting and winding with a vermicular 

 motion, swells up. The places where the dissolved gelatinous 

 matter is lying are seldom coloured, but are generally surrounded 

 by a spiral, or else dark lines separate themselves sideways from 

 the cotton gelatine, some of which also lie here and there in 

 fragments. These ribbon-shaped pieces, which have withstood 

 the action of the reagent, and which Dr. Cramer considers to be 

 the cuticle of the cotton fibre, are always more darkly colom'ed 

 than the magma or the solution. According to the nature of the 

 dye, either the original colour is retained, or it undergoes a cer- 

 tain amount of change ; but it is always obvious that it is to 

 these parts of the cotton that the colouring matter and the mor- 

 dant have adhered. Pig 6 represents the phfenomenon de- 

 scribed. I have observed this in the case of logwood-blue, log- 

 wood-violet, gall-black, brown, chrome-yellow and orange, Tur- 

 key-red, madder-red, prussian blue, and several other colours. 



Amaranth, dyed by means of murexide, presented the same 

 appearance, only that at the same time colouring matter was 

 clearly observed to have been laid up in the interior of the fibre. 

 In this almost exceptional case the question arises, whether this 

 is not to be attributed to the action of the corrosive sublimate, 

 which is very seldom in any other case employed in dyeing. 



That the tubular form of the cotton fibres is at least no essen- 

 tial condition to their taking a dye, appears from the fact that 

 the amorphous cotton gelatine, precipitated from the solution of 

 cuprate of ammonia, may be mordanted and dyed like other 

 cotton. 



l''rom these observations it follows, that the adhesion of the 



