IMPROVED COTTON" AIRPLANE FABRIC. 27 
wide differences between the stretch of the warp and the filling in 
the 2/60's fabric, and also give a comparison of the fabrics obtained 
from the three varieties of cotton used. The wide differences be- 
tween the stretch in the warp and the filling in the 2/60's cloth as 
compared to the 3/80's cloth is probably due to the greater number 
of ends and picks per inch in the 2/60's cloth, and also to the 
number of single threads plied in its manufacture. 
LABORATORY TESTS. 5 
Realizing that tests to produce an improved airplane fabric would 
be incomplete without a consideration of mercerization and " doping " 
properties, investigations were conducted regarding these properties 
in the chemical laboratory of the New Bedford Textile School and at 
several cloth-fininshing plants. These tests consisted of detailed 
study by laboratory experiments to determine the effect of the various 
contributing agents to mercerization and doping and the application 
of these results on a commercial scale. The laboratory tests were con- 
ducted on pieces of cloth 8 inches wide by 12 inches long inserted 
between horizontal jaws of a special cloth-testing machine equipped 
with a trough in which the various chemicals could be held, thus 
producing small samples closely resembling those produced under 
commercial conditions. These samples were tested according to the 
specifications of the Signal Corps as given on pages 4 to 9 for final 
results relating to the breaking strength and the ctretch. Other tests 
were made in which the cloth was subjected to continual stresses and 
microscopic examination. 
MERCERIZATION. 
To determine the best conditions for mercerization, preliminary 
tests were conducted to ascertain the strength of the caustic, the ten- 
sion during the treatment, the temperature of the caustic, the length 
of treatment, and the effect of additions of other chemicals to the bath. 
In these tests commercial caustic soda was used, a fresh solution being 
made from the same lot of dry caustic for each batch mercerized, so as 
to eliminate any variations in the process. These tests indicated that 
the best results could be obtained under the following conditions : 
(a) One hundred four degree Twaddle solution of caustic soda, figure 9. 
(6) Highest tension possible when neutralizing, figure 10. 
(c) Highest possible temperature of wash water, figure 11. 
(d) Time interval of one minute or less before neutralizing, figure 12. 
(e) No additions of silicate of soda or other chemicals, figure 13. 
5 These tests were conducted by Prof. Everett H. Hinckley, head of the chemical and 
dyeing department of the New Bedford Textile School, in collaboration with the Bureau of 
Markets, 
