.S7A 1 WILLIAM SIEMENS, F.R.S. 243 



GAS AND ELECTRICITY AS HEATING AGENTS, 



.1 l.rrture delivered at Glasgow on Thursday, 27th January, 1881, 

 i/m/cr the auspices of the Glasgow Science Lectures Association. 



BY C. WILLIAM SIEMENS, D.C.L., LL.D., F.R.S. 



ON the 14th of March, 1878, I had the honour of addressing 

 you " On the Utilization of Heat and other Natural Forces." I 

 thru showed that the different forms of energy which Nature has 

 provided for our uses, have their origin, with the single exception 

 of the tidal wave, in solar radiation ; that the forces of wind and 

 water, of heat and electricity, are attributable to this source, and 

 that coal forms only a seeming and not a real exception to the 

 rule, being the embodiment of a fractional portion of the solar 

 energy of former geological ages. 



On the present occasion I wish to confine myself to one branch 

 only of the general subject, namely, the production of heat energy. 

 I shall endeavour to prove that for all ordinary purposes of heat- 

 ing and melting, gaseous fuel should be resorted to, both for the 

 sake of economy, and in order to do away with that bugbear of 

 the present day, the smoke nuisance, but that for the attainment 

 of extreme temperatures the electric arc possesses advantages, 

 unrivalled by any other known source of heat. 



Carbonaceous material such as coal or wood is practically inert 

 to oxygen at ordinary temperatures ; but if wood is heated to 

 295 C. (593 Fahr.), or coal to 826 C. (617 Fahr.), according to 

 experiments by M. Marbach, combination takes place between 

 the fuel and the oxygen of the atmosphere, giving rise to the 

 phenomenon of combustion. It is not necessary to raise the 

 whole of the combustible material to this temperature, in order to 

 continue the action ; the very act of combustion when once set in, 

 gives rise to a development of heat more than sufficient to prepare 

 additional carbonaceous matter, and additional air for entering 

 into combination ; thus a match suffices to ignite a shaving, and 

 this in its turn to set fire to a building. 



The first effect of combustion is therefore to heat the combus- 



B 2 



