Scientific Intelligence. 



105 



SCIENTIFIC INTELLIGENCE. 



L CHEMISTRY AND PHYSICS. 



I. On the production of very high temperatures. — Sainte Claire 

 Deville has published an extended description of the methods em- 

 ployed in his laboratory to produce high temperatures, and his paper 

 possesses great value and interest. For operations on a small scale, De- 

 ville employs a lamp of peculiar construction in which the vapor of oil 

 of turpentine or any other liquid hydro-carbon is completely burned by 

 means of a powerful artificial blast of air. The lamp in question would 

 be scarcely intelligible without a figure, and we must refer for fuller de- 

 tails of its construction to the original memoir. By its means a heat 

 sufficient to melt feldspar can be easily produced, provided that the table 

 bellows employed is of sufficient size and power. [We have found it in 

 practice less safe and convenient than the gas blast lamps with sixteen 

 jets, introduced by Sonnenschein, but it gives a higher temperature, 

 w. G.J The other apparatus described by the author is a blast furnace 

 in which platinum and many other substances can be fused. It consists 

 of a cylinder of fire-clay 18 centimeters in diameter and somewhat 

 higher than its width. This may be surmounted by a dome to prevent 

 the escape of the coals from the force of the blast. This cylinder rests 

 upon the edge of a hemispherical cavity connecting with a good forge 

 bellows. A circular piece of cast iron pierced with openings about 10 

 millimeters in diameter and disposed round the edge of the plate forms 

 the bottom of the cylinder and separates it from the cavity below. The 

 author employs as fuel, cinders from the hearth of a furnace heated with 

 the dry coal of Charleroy. These cinders are found mixed with pieces 

 of coal and are sifted upon a sieve with square holes of 2 millimeters in 

 the side. What passes through the sieve is rejected. The coals em- 

 ployed must vary from the size of a small pea to that of a nut. The 

 crucible is placed in the centre of the cylinder and surrounded with 

 kindled wood, upon which pieces of coal of the size of a nut are laid 

 and upon these the proper fuel of the furnace. The blast is then forced 

 in slowly and gradually increased. The force of the maximum tempera- 

 ture begins about 2 or 3 centimeters above the iron plate and is only 7 

 or 8 centimeters high. The coals above remain cold from the trans- 

 formation of the carbonic acid into carbonic oxyd, which gas in the 

 author's furnace burns with a flame 2 meters in height. The heat pro- 

 duced by this arrangement is called by the author the " blue heat," from 

 its peculiar tint. In it the best ordinary crucibles run down like glass. 

 The author uses three kinds of crucible. The first is of quicklime and 

 is made of well burned lime slightly hydraulic, which is cut with a knife 

 or saw into prisms with a square base 8 or 10 centimeters in the side 

 and 12 or 15 centimeters high. The edges are rounded and a hole is 

 made in one end of convenient size. Sometimes an inner crucible is 

 used, each having its own cover. When the substance to be heated is 

 very refractory, only one crucible is used and the walls of this are made 

 3 or 4 centimeters thick. The base of the crucible must be 5 or 6 cen- 



SECOND SERIES, VOL. XXII. NO. 64. — JULY, 1856. 14 



