394 Miscellanies. 



fifty minutes. A wire of cast steel wliicii maintained the vibrations 

 of its suspended weiglits 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 

 cast iron 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 a 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 elasticity 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. 



Soft metallic wires and springs without temper, will not vibrate 

 well. A copper wire is unsuited for these purposes ; a brass wire 

 is suitable in proportion to the quanuty of zinc in its composition,,so 

 that it does not exceed one half; the usual proportion is four parts 

 of copper 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 vm&.—Lo7id. Jour, of Jlris and Sciences, 

 Mar. 1831. 



3. Manufactured articles frojn Horns and Hoofs. — A patent was 

 enrolled, March 1829, to J. & T. Deakin, of Sheflield, 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 escutcheons, coverings for doors and window 

 shutters, finger plates, knobs and handles of table knives and forks, he. 



The method of making some of these articles is thus stated ; 



In making a ring of horn, the required piece is first cut out of the 



3, of its proper dimensions, and nearly in the shape of a horse 



