of Heat for Chemical Operations. 251 



nary temperature. Mixed with the amount of air necessary 

 for their complete combustion, it occurred to me, their vapours 

 would form an efficient substitute for coal-gas. This method 

 I have tried, and found to yield excellent results. 



The vaporization is effected by passing a brisk current of air 

 through a column of the liquid, sufficient being vaporized to 

 yield an exceedingly efficient combustible mixture. 



The apparatus used is exceedingly simple and of trifling 

 cost, the liquid hydrocarbons used being either common me- 

 thylated ether, benzol, naphtha, or common alcohol. The 

 mixture of the benzol hydrocarbons, almost universally sold 

 and known as " benzoline" is preferable, on account of its 

 small cost and its higher volatility. 



A moderately tall and rather narrow cylinder (like those 

 used in the Wanklyn process of water- analysis, or even a large 

 test- or boiling-tube) is fitted with a good cork, through which 

 pass two tubes analogous to those of an ordinary wash- 

 bottle : one passes to the bottom of the cylinder and serves as 

 an ingress-tube for the current of air, the other (just entering 

 through the cork) serving for an egress-tube. The cylinder 

 being almost filled with the volatile liquid, a brisk current of 

 air is passed through, and the air, saturated with vapour, led 

 off from the egress-tube to an ordinary Bunsen burner, where 

 a steady and intensely hot flame is obtained. By regulating 

 the current of air or vapour by means of a tap, the name can 

 be varied with the same facility as that of an ordinary gas- 

 flame. 



The current of air may be maintained by means of a large 

 gas-holder, a reversible aspirator like that used by Dr. Angus 

 Smith, or even a foot-bellows. By fitting up a large test-tube 

 in the manner described, and by using a small foot-bellows, 

 an exceedingly portable apparatus is obtained. For the supply 

 of a small laboratory where a number of lights are required, 

 the apparatus can be varied with equal facility and at very 

 trifling expense. The vaporizing-cylinder may be replaced by 

 a metallic vessel, or a tall, somewhat narrow bottle ; and a con- 

 tinuous and powerful supply of air can be maintained from the 

 apparatus described by 1*. Casamajor* in the l American 

 Chemist.' This apparatus, being worked by the supply of 

 water from one of the service water-taps, needs scarcely any 

 attention; and thus a continuous supply of combustible vapour 

 can be maintained. The egress-tube from the cylinder must 

 be furnished with branch pipes or T-pieces, as an ordinary 

 gas-pipe. 



The combustion of these vapours, it will be observed, gives 

 * 'American Chemist,' vol. iv. p. 361. 



