S/fi WILLIAM SIEMENS,, F.R.S. l8l 



difU'ivnt means altogether, such as the electric arc, because com- 

 bustion, however carried on, would not give us a higher tempera- 

 ture, even if we found materials that would resist the heat. These, 

 thru, are some of the advantages which may be claimed in favour 

 of gaseous fuel. 



Fuel may be dealt with in two ways in order to produce gaseous 

 fuel ; it may be placed in a retort, and the retort heated by the 

 external application of heat in order to drive out the volatile con- 

 st .imciits. This is the process, as you are aware, generally followed 

 in gas-works. The use of gas for illuminating purposes dates 

 from the end of the last century. It was in the year 1792 that 

 Murdoch, of Soho, erected his gas- retort. After him Lampadius 

 published, in 1801, his investigation, very crude according to our 

 present ideas, on the subject of gas, and gas illumination, but it 

 was not until 1815 that gas illumination came to be practically 

 used, and it was applied first of all, I believe, in London. This 

 mode of producing gas by heating a retort, gives rise to two prin- 

 cipal products, the gas or gaseous fuel, and the residue, the car- 

 bonaceous matter, or coke. Both these constituents are very 

 suitable for heating purposes. Coke has this advantage over raw 

 coal, that it burns without developing smoke, and it is, therefore, 

 applicable for many purposes where this rapid development, or 

 change of the solid fuel into gaseous constituents, would absolutely 

 impede the operations to be performed, such as blast furnaces, or 

 locomotive engines. The gaseous fuel produced in the retort is 

 also applicable for heating purposes, but has hitherto been used 

 chiefly as an illuminating agent. I shall presently refer to the 

 working of a gas retort, with a view of showing that, although 

 we treat the gas coming from the retort as illuminating gas, as an 

 entity, it really consists of many constituents, and that the quality 

 of the mixture of gas coming from such a retort at one portion 

 of the process is very different from that which comes from it at 

 other portions. If the purpose before us is the heating of a fur- 

 nace, and our object is to obtain from the solid coal as much 

 gaseous fuel as possible, then it would not be desirable to have 

 resort to a retort. The retort process is a slow one, and the coke 

 produced, although it can be used also as fuel, would be undesirable 

 at works where no such fuel is required, where the only object is 

 to heat furnaces for melting glass, for making steel, for heating 



