252 THE. ADDRESSES, LECTURES, ETC., OF 



tive rods d project upward from the circumference of the copper 

 chamber or tube b. The rods are coated with platinum or nickel 

 to prevent oxidation when heated (almost to redness) by the heat 

 of the flame. The tube b is perforated on its circumference, and 

 surrounded with several layers of wire gauze e presenting a con- 

 siderable aggregate surface. Its bottom surface is formed of a 

 perforated disk covered with a similar thickness of wire gauze/, 

 through which the external air finds access to the burner, and in 

 so doing becomes considerably heated. 



The waste heat of the flame, or that portion of the heat pro- 

 duced in combustion which is not utilized as luminous rays, 

 serves to heat the air by which combustion of the gas is sup- 

 ported to some 500 or 600 Fahr., giving rise to a more brilliant 

 flame, and consequently to a greatly increased output of light 

 for a given consumption of gas. 



But not only the quantity of light but its quality is improved 

 by the higher temperature attained. It may appear surprising, 

 but it is a fact susceptible of accurate proof, that the light 

 obtained in consumption of a given amount of gas is thus in- 

 creased by some 40 per cent., and in this large proportion the 

 deleterious influences connected with gas lighting may be dimin- 

 ished. Gas will thus be better able to hold its position against 

 its more brilliant rival the electric arc, except for such large 

 applications as the lighting of public halls, and places, of har- 

 bours, railway stations, warehouses, &c., for which the latter is 

 pre-eminently suited. Add to these improved applications of gas 

 the ever-increasing ones for heating purposes, and I have only 

 to express regret that I am not a gas shareholder. 



If gas is to be largely employed, however, for heating purposes, 

 it will have to come down in price ; and considering that heating 

 gas need not be highly purified, or possessed of high illumi- 

 nating power, the time will come, I believe, when we shall have 

 two services ; and as in many towns two systems of gas mains 

 already exist, it would only be necessary to appropriate the one 

 for illuminating and the other for heating gas. The ordinary 

 retorts could be used for the production of both descriptions of 

 gas, it being well known that even ordinary coal will give up 

 gases of high illuminating power during a certain portion of the 

 time occupied in their entire distillation. The gases emitted from 



