1912] on Electricity Supply : Fast, Present and Future. 447 



combustion engine is because in this machine the temperatures that 

 can be successfully dealt with are very high. In the cylinder the 

 combustion takes place when the gas is in considerable mass, and 

 though those portions of it which are in contact with the walls of 

 the cylinder become cooled, still, the interior of the mass keeps 

 very hot, indeed, at temperatures which could not possibly be em- 

 ployed in turbines, unless we could find the materials of which to 

 construct the blades which would maintain their tenacity while run- 

 ning at a red heat. It is conceivable that the science of metal- 

 lurgy may be able to provide new metals or alloys with the necessary 

 properties for doing this in the future, but at present no such material 

 exists, and the only way in which the internal combustion turbine can 

 for the moment be worked is by reducing the temperatures of the gases 

 by the incroduction of water, steam, or air, to a reasonable amount ; 

 indeed, in practice the temperature has to be reduced to that usual 

 with superheated steam, when of course, according to the formula 

 quoted, the maximum efficiencies theoretically obtainable with the 

 internal combustion engine and the steam turbine become equal. 

 Even then, if other things were equal, the internal combustion tur- 

 bine miglit have some advantage by doing away with boilers : but, 

 unfortunately, there are other difficulties — such as the bad economy 

 of all methods of compressing the gaseous mixture as is necessary to 

 obtain the full advantage of its combustion. 



No doubt the future of electricity supply lies with very large 

 stations employing very big units of plant, and combining the gene- 

 ration of electricity with chemical manufacture, the electricity on the 

 one hand, and the chemicals on the other, being by-products each of 

 the other's manufacture. So far as this country is concerned, for 

 electricity supply at all events, we are not likely to depart from the 

 use of coal as long as that source of energy holds out. For the pro- 

 pulsion of ships oil may present advantages, but on land, in Great 

 Britain, coal must remain the cheaper. In all probability, however, 

 in the future the coal will not be simply burnt. Undoubtedly it will 

 have to be turned into gas, and the sulphate of ammonia and the tar, 

 with all its interesting constituents, saved. Whether the gas will be 

 burnt under boilers for the raising of steam to supply steam turbines, 

 or whether it will be used in internal combustion engines, will depend 

 on the progress made by the latter in respect to attaining larger 

 dimensions, and also as regards improvements in tlie gas firing of 

 boilers, in respect of which, as has recently been shown at the Royal 

 Institution by Professor Bone in his interesting lecture on Surface 

 Combustion, there is still much to be done. 



Anyway, future generating stations are almost certain to be estab- 

 lished — not in the large towns, but at the coalfields, and, instead of 

 the coal, the electricity will be transmitted at high pressure to where 

 it is required. Sir William Ramsay's somewhat revolutionary scheme 

 for the manufacture of gas by ignition of the coal in the seam itself 



