majstufactueixg tests of cottox. 9 



30 minutes in cold water, squeezed, and treated 2.5 hours cold with 

 " electrolytic chlorine," 1.46 grams of chlorine per liter ; was rinsed 

 well, treated 30 minutes in a 5 per cent solution bisulphite of soda, 

 cold; was rinsed well, and blued with a solution containing three- 

 fourths of a gram vat blue in 10 liters of water. 



Samples 10, 11, 14, and 15 were combined into one lot, samples 

 8 and 9 into a second lot, and samples 12 and 13 into a third lot, and 

 each lot was bleached by the method outlined in the pre\'ious para- 

 graph for samples Nos. 2 and 2a. 



By comparison of these samples it was evident that there was as 

 much difference in blea<ihing quality between the two bales of non- 

 fumigated cotton as there was between the bales of fumigated and 

 ronfumigated cotton of the same quality. 



DESCRIPTION or FURTHER TEST. 



Samples of fumigated and non fumigated Chinese cotton which 

 had been both bleached and blued by a representative cotton mill 

 were submitted for examination. As a result of the bluing process, 

 the sample of fumigated cotton was a more intense blue-than the sam- 

 ple of nonfumigated cotton. On receipt, tests were made on these 

 samples for iron to ascertain if there had been a formation of Prus- 

 sian blue, due to the presence of hydrocyanic acid in the fumigated 

 cotton, which would cause the intensifying of the color of the cotton. 

 Negative results were obtained. The bluing matter was extracted 

 with water until the samples were practically the same color. These 

 water extracts were of different depths of blue. The deepest extract 

 was then diluted imtil both were of the same shade of blue. The 

 extracted cotton samples were treated again in their respective solu- 

 tions. The resultant samples were of the same color. 



From the above results the conclusion was reached that the in- 

 creased depth of blue on the fumigated sample was because it had 

 been treated with a greater quantity of bluing and not because of the 

 presence of hydrocyanic acid or because of any chemical change in 

 the fiber such as the formation of hydrocellulose. 



test for the presence of hydrocyanic Acm. 



Small specimens from each of the following samples, 2, 2a, and 

 8 to 15 inclusive, were tested for the presence of hydrocyanic acid as 

 follows : 



The sample was covered with a solution of 10 c. c. of distilled 

 water, 5 drops concentrated sulphuric acid, 5 c. c. 2/normal ferrous 

 sulphate and 6 c. c. normal sodium hydroxide heated nearly to a lx)il, 

 then 5 c. c. 6/normal hydrochloric acid were added. 



These tests gave no blue coloration which indicated the absence 

 of hydrocyanic acid in all of the samples at the time of treatment. 



