394 MR. c. o'neill*s experiments and 



cially adapted ; the only precaution necessary is to keep 

 the floating cylinder from contact with the sides of the 

 containing vessel, which is easily done by means of guides, 

 either fixed on the cylinder or acting from above. 



XXIX. — Experiments and Observations upon Cotton. 

 By Charles O'Neill, Esq., F.C.S. 



Head November 17th, 1863. 



Some years ago I commenced a research into the chemical 

 principles of cotton- dyeing, with a view to elucidate several 

 disputed questions concerning the bearings of dyeing-phe- 

 nomena upon chemical laws in general. Like most other 

 experimenters in this field, I began upon cotton cloth, but 

 soon found no scientific data were to be obtained from the 

 fibre in the woven state, since only those fibres and parts 

 of fibres which were exposed on one side or other of the 

 cloth came into contact with the reagents, the great bulk 

 not being at all acted upon. In yarn this objection was 

 only lessened, not removed ; and when at length I found 

 in many instances that a single fibre of cotton, less than 

 Q^-Q of an inch in diameter, might be dyed upon one of its 

 flattened sides and quite colourless on the other, it became 

 clear that experiments should be made upon the primary 

 fibre. In consequence my attention was turned to it ; and 

 although the main object of my experiments has not been 

 attained, I have collected a number of observations which, 

 having been made with great deliberation and exactness, I 

 wish to communicate and put on record concerning the 

 fibre. 



Theiterm " cotton fibre '^ has a kind of collective signifi- 

 cation, meaning a mass of cotton fibres^ and, if used for the 



