PRESIDENTIAL ADDRESS— SECTION A. 1 7 



maximum of 10 to 12 per cent., while large turbines of the 

 latest design have brought up the efficiency to about 18 to 19 

 per cent. 



The development of the steam turbine in central station 

 service has been etremely rapid. In the year 1903 several 500 

 K.W. steam turbines were erected in the Great Fisk Street 

 Station of the Commonwealth Edison Company of Chicago, but 

 these were speedily replaced by 1.200 K.W. units, and one of 

 the original turbines was erected in the centre of the park of the 

 General Electric Company at Schenectady as a memorial of 

 the rapid development of the turbine. Quite recently Messrs 

 Parsons have contracted to build a turbo-alternator of 25,000 

 K.W. capacity for this same station, so that in nine years the 

 size of the turbine has increased fifty fold. This large generat- 

 ing unit is expected to show an improvement in steam consump- 

 tion of 10 per cent, compared with the best existing plant, and 

 this seems to point to the direction development in electrical 

 generating plant is likely to take for some years to come. 



Very great difficulties occur in the development of internal 

 combustion engines of large size, and it is unlikely that they will 

 be employed to any appreciable extent for use in central elec- 

 tricity supply stations until a satisfactory rotary type can be 

 evolved, and the difficulties in the way of this type are perhaps 

 greater and involve many problems, such as the finding of a 

 material that will stand very high temperature without losing 

 its tenacity. 



For plant of from 500 to 1 .000 K.W. size, and smaller, the 

 internal combustion engine will doubtless continue largelv to be 

 used. 



Among other prime miners which have a promising future 

 before them, the Diesel oil engine deserves to be mentioned, 

 more especially as this engine approaches in efficiency more 

 closely to the ideal or perfect heat engine than any other 

 Almost any kind of oil. whether animal, mineral or vegetable, 

 can be used effectively in this engine. Some few months ago 

 experiments were carried out in the Congo for the French 

 Government to ascertain whether it was feasible to utilise the 

 oil obtained from " monkey " nuts in this engine, and T am 

 informed that the results were very satisfactory indeed, and 

 such as to render the engine particularly useful in tropica! 

 countries where coal is expensive and " monkey " or ground 

 nuts can be grown cheaply. 



The Shuman sun-power plant is another prime mover which 

 may be developed for use in tropical climates, especially since 

 it is held that 10 per cent, of the earth's land surface will even- 

 tually depend upon sun-power for all mechanical operations. 

 This plant consists of an absorber, a low-pressure steam-engine, 

 condenser and auxiliaries. The absorber is composed of a 

 series of units, each containing a flat metal honeycomb watei 

 vessel, rectangular in shape. This vessel is enclosed in a flat 



