Miscellanies 



181 



esis of Cbevreul, that the fatty substances are compounds analogous 

 to the ethers, is thus verified in the case of spermaceti. — D. 



30. On the improvements lately introduced into the Iron Foun- 



>f 



)— M 



(Ann, des Mines, T. vn, 



gained some ground, that any advantage results from the employ- 

 ment of heated air in furnaces, apart from the increased elastic force 

 it thus receives, and states that a much greater heat is obtained, and 

 a less consumption of coal required, when the air is made to enter 

 with great force, that is, from a previous state of compression. M. 

 Knauff, member of the scientific Society of Mines at St. Petersburg, 

 by experiments made at the expense of government, finds that a 

 hundred cubic feet of air, thrown into the furnace, under a pressure 

 of two inches of mercury, produce the same result as two hundred 

 cubic feet of air, under the pressure of an inch of mercury, with this 

 difference, that in the latter case double the quantity of charcoal is 

 consumed. 



i 



The economy in the use of coal, attained by some of the Rus- 

 sian mines, by the above means, is worthy of remark* In the foun- 

 deries of the heirs of Raztorgonief, where are thrown out, in twenty 

 four hours, seven hundred poods (nearly twenty five thousand three 

 hundred pounds avoirdupois) of cast iron, only five hundred poods 

 (nearly eighteen thousand pounds avoirdupois) of charcoal, (princi- 

 pally of birch wood,) is consumed, whilst formerly twice this quan- 

 tity was used, for the same quantity of iron. In fact, since 1S06, 

 eighteen founderies of the Oural have annually economized nearly 

 five thousand two hundred cubic feet, principally by a proper regu- 

 lation of the quantity and pressure of the air — the former of these 

 particulars is attained by varying the size of the tuyere, and the lat- 

 ter determined by a manometer. 



The above results seem to prove a much greater effectiveness and 

 economy in the process above described, than results from the use of 

 heated air. — D. 



31. Cause of Dynamic phenomena. (L'Institut, No. 113.) — M. 

 Pelletier states the following facts, in support of the opinion he has 

 advanced, that the transitory motion produced by every change in 

 the molecular state of a body, is the immediate cause of dynamic 

 phenomena. 



