12 



BULLETIN 366, U. S. DEPARTMENT OF AGRICULTURE. 



From Table VIII it will be seen that tlie gain in tensile strength 

 due to mercerization is a trifle greater for the nonf uniigated than for 

 the fumigated cotton. 



The tests for the degree of mercerization were made by dyeing 

 samples of the fumigated and nonfumigated mercerized yarns in 1 

 per cent benzo purpurin 4 B, 10 per cent salt, 1 per cent soluble oil, 

 30 minutes at 160°, volume of bath equal to 100 times the weight of 

 goods treated. The same weight samples of mercerized Egyptian 

 yarn were dyed in the same bath after dyeing the fumigated and 

 nonfumigated samples. These exhaust skeins furnished a means of 

 measuring the degree of mercerization, for the better mercerized 

 samples absorb more dyestuff and consequently leave less in the dye 

 bath. In order to ascertain more accurately the degree of merceriza- 

 tion, a sheet of samples was prepared by dyeing mercerized Egyptian 

 cotton with the percentages of dyestuffs shown in Table IX. Salt 

 and soluble oil was used as in method given above, benzo purpurin 

 4 B being used as the dyestuff. 



Table IX.— ^ set of color standards. 



Standard No . 



Dye, per cent 



Sa'lt, per cent 



Soluble oU, per cent 



Standard No . 



Dye, per cent 



Salt, per cent 



Soluble oil, per cent 



Standard No . 



Dye, percent 



Salt, per cent 



Soluble on, per cent 



1 



2 



3 



4 



5 



6 



7 



8 



5 



4.5 



4 



3. 5 



3 



2.5 



2 



1.5 



20 



20 



20 



20 



20 



20 



10 



10 



2 



2 



2 



2 



2 



2 



1 



1 



0.9 

 10 

 1 



O.S 

 10 

 1 



0.7 

 10 



0.6 

 10 

 1 



0.5 

 10 

 1 



0.4 



10 

 1 



0.3 

 10 

 1 



0.2 

 10 

 1 



18 



0.1 

 10 

 1 



19 



20 



21 



22 



23 



24 



25 



26 



0.09 



o.os 



0.07 



0,06 



0.05 



0.04 



0.03 



0.02 



10 



10 



10 



10 



10 



10 



10 



10 



1 



1 



1 



1 



1 



1 



1 



1 



27 



0.01 

 10 

 I 



The samples of colored yarns obtained by dyeing in the exhaust 

 bath were matched against the standards, and it was found that 

 cotton No. 2a (nonfumigated 1^-inch Egyptian cotton) dyed a lighter 

 shade, indicating a greater degree of mercerization than cotton No. 2 

 (fumigated 1^-inch Egyptian cotton). But results from lots 1 and la 

 fumigated and nonfumigated, respectively, were practically identical. 



CONCLUSION. 



The results of these tests indicate that the fumigation of cotton 

 with hydrocyanic-acid gas does not affect, to any material extent, 

 the percentages of waste, spinning qualities, tensile strength, bleach- 

 ing, dyeing, or mercerizing properties of the cotton. 



WASHINGTON : GOVEUNMENT PRINTING OFFICE : 1916 



