Although impossible to perfectly accomplish this, (_i. e._, the surrounding of body in a stationary envelope of air), that cloth or fabric which most nearly approximates this, other things being equal, will prove itself the warmest as well as best adapted for evaporation of cutaneous moisture. Such a nearly stationary air occurs naturally in the various pelts, and although in many the integument is visible beneath, yet they can withstand the most rigorous weather. Thus Krieger's experiments with tin cylinders containing hot water with two coverings of different materials, between which an interval of 1/8 to 1/4 inch was left, proved (after subtracting the amount due for conduction) the impediment to radiation by the second layer to be, _viz_: linen, 32; silk, 32; flannel, 29. Thus showing that the stationary air, rather than the material out of which the second layer was made, was the main factor in preventing radiation. He then experimented with single and double layers of the same material surrounding these cylinders, obtaining the following instructive results; the numbers representing the proportionate loss of heat through double to single layers, the losses through the single ones being taken at 100: Double Stuff, ("Doppel Stoff") Fleece-lined cotton 69-76 Buck-skin 74-86 Flannel 86 Home-spun linen 91 Stout, extra heavy silk 94 From these results the conclusion is obvious that the substance and its weight are of less consequence, where _radiation_ is in question, than its texture and volume. Believing that the explanation was due to the "residual air," experiments have been made with loose wadding, noting the rapidity of fall of temperature, on compressing the same wadding, when the fall was far more rapid. Again, the loss of heat through a rabbit's fur being taken as 100, when shorn of its hair it rose to 190; and further destroying its porosity by a coating of gum-arabic, it rose to 296. (Dict. Hygiene.)