114 EEPORT — 1878. 



Bray's " Special " Union Jets foe Street Lamps. 



Many years ago Mr. Scholl, of London, adopted the system of placing 

 a small plate of platinum between the two orifices of the union jet, the 

 result being that the initial velocity with which the gas escapes is spent by 

 striking against this plate, and the gas ascends in a somewhat sluggish 

 flame, which, in the case of cannel-gas, has a tendency to smoke, and is 

 easily blown about by currents of air. This is the case also with all 

 union jet flames burned at very low pressures, aud practically a jet of this 

 kind cannot be burned much below 3 or 4 tenths for small sizes and 5 tenths 

 for large sizes consuming 4 or 5 cubic feet per hour. Scholl's " perfecter," 

 as he has called it, has been used extensively in London and other towns 

 for common gas, but it is not suitable for the richer gas used in Scottish 

 towns. 



A flame formed by a jet of gas issuing with considerable velocity 

 possesses a certain degree of stiffness, and resists, to some extent, the 

 influence of currents of air. This is particularly necessary in the case of 

 cannel-gas, since, whenever the flame is much deflected by air currents, a 

 portion of the carbon arising from the heating of the richer hydrocarbons 

 (e.g., olifmes, benzole, &c.) passes off unconsumed, and a smoky flame is 

 the result. In practice it is necessary to sacrifice a certain proportion of 

 the possible illuminating value in order to give the flame sufficient stiff- 

 ness to resist currents of air. 



Next to the union jet, the " batwing " is that most commonly used for 

 burning gas. It is simply a little tube closed at one end in which a 

 straight slit is cut, varying in breadth from about two-tenths to one 

 millimetre. It is made of cast iron, brass, porcelain, or steatite ; the best 

 form being that having a brass body and steatite top. The flame of the 

 batwing is wider and shorter than that of the union jet, and in order to 

 be equally effective requires to be burned at lower pressures. It is 

 particularly adapted for large flames burning from 3£ to 5 cubic feet of 

 gas per hour. With rich cannei-gas (25 to 30 candles) it gives results at 

 least equal to the union jet, and with gas of 18 to 22 candles it is decidedly 

 superior. 



