108 Professor Calvert on the Action of 



On the Action of Organic Acids on Cotton and Flax Fibres. 

 By F. Crace Calvert, F.C.S., M.R.A. of Turin, Professor 

 of Chemistry, Royal Institution, Manchester. 



I am induced to publish the facts contained in this paper, 

 because they are interesting in themselves, and are likely to 

 prove important in certain arts, especially that of calico-print- 

 ing ; for it appears, contrary to the generally received opinion, 

 that the organic acids exert a corrosive action on cotton and 

 flax fibres, which, in some instances, is nearly as marked as 

 that of the weaker mineral acids. 



My attention was drawn to this subject by having a cambric 

 handkerchief placed in my hands for examination, the tex- 

 ture of which was injured in all such parts as had been in 

 contact with an isinglass jelly, sold by a confectioner as made 

 from calves' feet. I soon ascertained that the jelly had been 

 clarified with tartaric acid, and not with any mineral acid ; 

 therefore I made a series of experiments with jellies prepared 

 by myself, and compared them with others procured from 

 some of the most respectable confectioners of our city, and I 

 found, as a rule, that cambric linen was materially injured 

 when it had been dipped in such a solution dried in the atmo- 

 sphere, and then heated to 126° C. 



As this interesting fact involved a question of great prac- 

 tical value to the calico printer, I deemed it my duty to examine 

 carefully the action of various organic acids on fibres, and the 

 following pages contain the results of my inquiry. 



The first question which presented itself was, whether the 

 injury of the fibres arose from the tartaric acid contained in the 

 jellies, or was to be attributed to the mechanical effect of a solid 

 substance interposed between the fibres of the fabric interfering 

 with their ordinary elasticity, and thus rendering them brittle. 



To appreciate the influence of tartaric, citric, and oxalic 

 acids, I dipped small pieces of cambric and muslin (pre- 

 viously well washed in distilled water) into a solution contain- 

 ing two per cent, of tartaric or oxalic acids, carefully purified, 

 and completely free from mineral acids. The pieces were then 

 dried in the atmosphere, and exposed for an hour to various 

 temperatures, and the results obtained are shown in Table I. 



Table I. illustrates an interesting fact, viz., that while two 



