......... 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. D|bereiner and Oesner,
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,
beside weakening the fibres of the stuff, so as to make it tear easily.
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