Aug. 19, 1918 
Influence of Humidity on Wool Fiber 
291 
hundred tested were, respectively, 269, 273, 275, 280, 283, and 288. 
The smallest and largest averages obtained from any two of these figures 
are 271 and 286, respectively. If each sample is taken into consider¬ 
ation, it will be observed that the average tensile strength is greater in 
every case at a humidity of 40 than at 60, 70, or 80 per cent. It will 
also be noted that the average tensile strength of every sample is greater 
at a humidity of 50 than at 70 or 80, and at 60 it is greater than at 80 
per cent. The tensile strength decreases with the increase in the humidi¬ 
ty, although in some cases there may be a slight variation up or down 
when the sample tested is compared with the one tested at the next 
higher or lower humidity. The average tensile strength of four samples 
at the different humidities gives figures which show a direct ascent as 
the percentage of relative humidity is reduced. It would seem that if 
an average of the four samples was taken, the effects of humidity upon 
the tensile strength of the wool fiber could be more clearly seen. Graphs 
of these averages are given in figure 1. 
It is again clearly noted that there is a direct increase in the tensile 
strength of the wool fiber as the relative humidity is reduced, and vice 
versa. The presence of more yolk on one fiber than on another would 
make an added variation, as would also the percentage error in the 
measurement of the fibers. 
The percentage elasticity of these four samples was determined at 
the same time as their breaking strengths, the results being given in 
Table IV. These: tests show that the wool fiber increases in elasticity 
as the humidity increases. Figure 2 shows curves plotted from the 
average elasticity of each of the four samples for each humidity, together 
with the average of all. 
It seems probable that each sample would show a curve in closer 
agreement with that of the final average of figure 2 had 500 or 1,000 
fibers been broken upon each sample at the different humidities. 
TabeE IV.—Percentage elasticity of wool fibers at five humidities 
Sample No. 
Number 
of fibers 
tested. 
Elasticity at a relative humidity of— 
40 per cent. 
50 per cent., 
60 per cent. 
70 per cent. 
So per cent. 
Per cent. 
Per cent. 
Per cent. 
Per cent. 
Per cent. 
991 . 
200 
28. 02 
31 - 74 
33-67 
34-88 
35 - S 2 
994 . 
200 
30.78 
33-32 
36. 92 
39.60 
42. 41 
996 ... 
200 
32.76 
38.38 
40. 24 
41. 26 
47-02 
997 . 
200 
19. 68 
26.30 
26. 44 
28. 64 
31 - 38 
Average.. .. 
27. 8r 
3 2 - 44 
34 - 32 
36. IO 
39.08 
The present paper is a progress report/and further humidity studies 
are being made, both with raw and clean wool. 
