394 Miscellanies. 
fifty a A wire of cast steel which maintained the vibrations 
of its suspended weights for ten minutes, continued them after it had 
passed to full blue (gros blue) an hour longer: 
From Dr. Thomson’s tables of cohesion, we learn that the power or 
force of cohesion of bar iron, is to that of cast iron nearly as seven- 
ty five to fifty; for to tear asunder rods of each species, an inch 
square at the base, it required seventy four thousand five hundred 
pounds avoirdupois, to destroy the cohesion of the particles of the 
bar iron rod, and fifty thousand one hundred pounds to break the 
ca. rod. ‘The elasticity or spirit of tempered steel springs ap- 
pears therefore, to be in an inverse ratio to their power of cohesion. 
An untempered wire of a harpsichord, maintained its vibrations for 
fourteen minutes; after being tempered to grey white, it maintained 
its motion nearly an hour. A wire of cast steel was tempered to 
gros bleu and then was diminished (i. e. untempered) and polished, 
‘in which state it vibrated only seventeen minutes, but upon the rev- 
enu @ gros bleu, it vibrated sixty seven minutes. ‘These general facts 
‘seem to show the great advantage of understanding the variations of 
tempering, as affecting the elaaicity of springs, and their consequent 
fitness for.any required purpose. M. Le Roy applied his knowledge 
to the formation of the best chronometer work of the period, in which 
art he gained a high reputation. ti 
ft metallic. wires and ‘springs without temper, will not vibrate a 
welt. A copper wire is unsuited for these purposes ; a brass wire ; 
is suitable in proportion to the quantity of zine in its composition, so 
that i it does not exceed one half; the usual proportion is four parts 
yper to one of zinc. Piano-fortes strung with wires tempered 
gros-bleu, were universally acknowledged by: amateurs, and by the 
Royal Academy of Paris to be superior in tone to instruments chord- 
ed with the usual steel wire. —Lond. Jour. of Arts and Science, 
Mar. 1831. 
. hers articles Sous Horns and Hoofs.—A patent was 
‘Sorblled, March 1829, to J. & T. Deakin, of Sheffield, for certain 
methods of making from. horns and hoofs, various articles, such as 
handles and’ knobs of drawers, curtain rings, bell pulls, door handles 
and knobs, key-hole escutchtons, coverings for doors and window 
shutters, finger plates, knobs and handles of table knives and forks. &e. 
The method of F making some of these articles is thus stated’: 
In making a ring of horn, the required piece is first cut-out of the 
” a of its proper dimensions, and nearly in the shape of a horse 
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