FURTHER STUDIES ON THE INFLUENCE OF HUMIDITY 

 UPON THE STRENGTH AND ELASTICITY OF WOOL 

 FIBERS 



By J. I. Hardy 

 Associate Wool Specialist, Wyoming Agricultural Experiment Station 

 INTRODUCTION 

 In a previous issue of the Journal the author published a preliminary 

 report^ of his work on the influence of humidity upon the strength 

 and elasticity of wool fiber. An attempt was made to obtain a better 

 method of testing wool in order that wool from sheep under various con- 

 ditions of breeding, feeding, and range management might be satisfac- 

 torily tested. A study was also made upon the strength and elasticity 

 of wool in an unsecured state under various conditions of humidity. 

 A review of the literature was given in the earlier report and will not be 

 repeated at this time. 



EXPERIMENTAL WORK 



After the work referred to above had been completed, further studies 

 were begun upon scoured wool. As in the previous work, all samples 

 were tested with a McKenzie fiber-testing machine. Wherever diameters 

 are reported they are the results of measurements with a micrometer 

 caliper unless othen^ase stated. This micrometer had a ratchet stop and 

 was graduated to read in hundredths of a millimeter. The micrometer 

 was used in the lower jaw of the testing machine and had a small hand 

 lens held stationary before it. With this arrangement it was possible 

 to interpolate the readings to o.ooi mm. The diameters of the fibers were 

 read at four different points. The smallest of these figures was in each 

 case used in computing the tensile strength of the wool fiber. 



Samples 991, 994, 996, and 997 had been extracted with ether and 

 washed with hot water and tested at each of five relative humidities, 40, 

 50, 60, 70, and 80 per cent, when the operator was suddenly called into 

 military service. The results of this work are given in Tables I and II. 

 Table I. — Tensile strength of wool fiber at five different humidities 



Sample No. 



Number of 

 fibers. 



At relative humidity of- 



40 per cent. 56 per cent. 60 per cent. 70 per cent. 80 per cent 



991. 



994- 

 996. 



997- 



100 

 100 

 100 

 100 



Mgm. 

 279. 22 



274- 77 

 295. 64 



215- 34 



Average . 



266. 24 



Mgm. 

 299. 47 

 280. 50 

 302. 00 

 210. 48 



Mgm. 

 289. 85 



279- 73 

 281.47 

 201. 87 



Mgm. 

 264. 29 

 255- 22 

 281. 40 

 200. 67 



Mgm. 

 258. 02 

 269. 59 

 271.83 

 196. 56 



273. II 



263. 24 



250-39 



249. 00 



1 Approved for publication in the Journal of Agricultural Research by the Director of the Agricultural 

 Experiment Station of the University of Wyoming. 



2 Hardy, J. I. influence of humidity upon the strength and the elastioty of wool fiber. In 

 Jour. Agr. Research, v. 14, no. 8, p. 285-296, 2 fig., pl. 48. 1918 Literature cite<l, p. 294-295- 



Journal of Agricultural Research, 

 Washington, B. C. 



(55) 



Vol. XIX. No. 3 

 Apr. 15, 19JO 

 Key No. Wyo.-3 



