Thermal Conductivity of Some Wearing Materials

Thermal Conductivity of Woolen, Cotton, Linen and Silk Materials.—Measurements of the conductivity of samples of knitted and woven materials have been made by the disk method of Lees, corrected for variation of emissivity with temperature. From one to eight or more layers of one of the materials were held between two copper disks with a pressure of 6 gm./${\mathrm{cm}.\mathrm{}}^2$, one disk being heated electrically by a coil between it and a third disk, and all three radiating to a constant temperature enclosure. The temperature of the samples was 30 to 40°. The values obtained are greater for dense than for loosely woven or knitted samples, ranging from 76 for unspun silk, 94 to 120 for wool, 101 to 122 for silk, 131 for flannelette, 158 to 167 for linen, to 168 to 184 for cotton, all times ${10}^{-6\mathrm{}}$. The results come out greater for several layers than for a few, and greater for moist than for dry samples. When the materials are arranged according to conductivity for equal weight instead of equal thickness, the order depends largely on the looseness of texture, beginning with unspun silk, loosely woven wool and knitted artificial silk, and ending with closely woven silk cotton and linen.