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Clothing.   113

Surrounded with- Seconds. Hare's fur .. .. .. 1312 Wood ashes .. 927 Charcoal .. .. .• .. 937 Lamp-black    1117

Among the substances here examined, hare's fur offered the greatest impediment to the transmission of the heat. The transmission of heat is powerfully influenced by the mechanical state of the body through which it passes. The raw and twisted silk of Rumford's table illustrate this" (Prof. Tyndall on Heat.)

Waterproof Cloth.-Cloth is made partly waterproof by rubbing soap-suds into it (on the wrong side), and working them well in : and when dry, doing the same with a solution of alum ; the soap is by this means decomposed, and the oily part of it distributed among the fibres of the cloth. (See " Tarpaulins.")

Incombustible Stuffs.-I extract the following paragraph from a newspaper. Persons who make much use of musquito curtains, will be glad to read it. " The Repertoire de Chimie Pure et Appliquee publishes the following remarks by the celebrated chemists, MM. Dcebereiner and CElsner, on the various methods for rendering stuffs incombustible, or at least less inflammable than they naturally are. The substances employed for this purpose are borax, alum, soluble glass, and phosphate of ammonia. For wood and common stuffs, any one of these salts will do ; but fine and light tissues, which are just those most liable to catching fire, cannot be treated in the same way. Borax renders fine textile fabrics stiff ; it causes dust, and will swell out under the smoothing-iron; so does alum, besides weakening the fibres of the, stuff, so as to make it tear easily. Soluble glass both stiffens and weakens the stuff, depriving it both of elasticity and tenacity. Phosphate of ammonia alone has none of these inconveniences. It may be mixed with a certain quantity of sal-ammoniac, and then introduced into the starch prepared for stiffening the linen ; or else it may be dissolved in 20 parts of water, in weight, to one of phosphate, and the stuff steeped into the solution, then allowed to dry, and ironed as usual,