488 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



as a natural regulator of the flow, and saving much waste of 

 heat. It may at first sight appear impossible to maintain 

 combustion under such circumstances; but we shall find a 

 solution of the difficulty in the fact that a light and heavy 

 gas being poured into a vessel at the same time, the light 

 gas will rise to the top while the heavy will sink to the bot- 

 tom. Thus, in the calorigen, the fumes of the gas are carried 

 out of the room without conveying away any of the air, and 

 also without employing the principle called draught, as there 

 is no communication between the furnace and the air of the 

 room. The door of the stove, when shut, completely cuts it 

 off, although it allows the light to be seen. 



The next important feature in this invention is the intro- 

 duction of a coil of wrought-iron tubing, which communicates 

 with the external atmosphere. This tube can be open to the 

 apartment ; and the air, entering and following the course of 

 the tubes, provides a plentiful ventilation, already raised to 

 a pleasant and healthful temperature. By this arrangement 

 the usual course of procedure is reversed; those nuisances in 

 an ordinary room, the spaces about the doors and windows, 

 instead of being fertile sources of draught and discomfort, 

 are the means by which the air passes out of the apartment, 

 Z A, October 14,1871,286. 



RENDERING KEROSENE INEXPLOSIYE. 



According to a French journal, if amyl-alcohol be added to 

 petroleum or mineral oils, it renders them inexplosive, even 

 when brought into contact with burning substances. This 

 is the discovery of M. Hurtault, who has taken out a patent 

 for it, 8 (7, 1871,1,11., 416. 



PURIFICATION OF COAL GAS. 



A method has been suggested by which coal gas can be 

 readily freed from sulphur, namely, by heating the impure 

 gas to redness, when the sulphur will combine with hydrogen 

 to form sulphureted hydrogen, which can be easily removed 

 by passing through a purifier containing the oxide of iron. 

 When coal gas, containing 30 grains of sulphur in 100 cubic 

 feet, was passed, first, through a red-hot tube, and then through 

 an iron purifier, the sulphur was reduced to about 5 or 6 grains. 

 The heat did not injure the quality of the coal gas, as, by 



