G.—ENGINEERING. 133 
blast. To conceive such a device was one thing, to give it being and 
action was quite another. That meant many subsidiary inventions 
and years of toil; it meant the removal of mountains of prejudice and 
difficulty. But the triumph is complete. Engineers, all the world 
over, are wholeheartedly converted. They build their steam windmills 
on a colossal scale, crowding 50,000 or 100,000, sometimes even 200,000 
kilowatts into a single unit, confident in the knowledge that no more 
trustworthy and economical prime-mover is available for the gigantic 
stations which play so important a part in modern civilization as centres 
for the production and distribution of light and of power. 
All these stations have come into existence in the fifty years which 
have passed since Bramwell made his prophecy and in them it has 
most conspicuously failed of fulfilment. Review the great power stations 
of the world, and you find their method of manufacturing electric energy 
from heat is almost wholly through the medium of steam. To illustrate 
how small a place is taken in them by the internal-combustion engine 
let me quote some figures for British power stations. A return 
published in 1930 by the Electricity Commissioners gives the aggregate 
capacity of the generative plant of various types as follows :— 
a 2 
; Kilowatts 
' Steam Turbines F ‘ ‘ 3 ; . 5,501,952 
: Reciprocating Steam Engines. ; , . 138,806 
; Oil Engines , : ' ; : st fd oes 
E Gas Engines ‘ : ‘ ‘ , : 17,473 
- Water-power Plant . ; : ; : . 42,208 
~ a 
You will see that oil engines and gas engines together make up only 14 
per cent. of the whole. And it is the case that abroad, as well as at home, 
the steam turbine is dominant. Its dominance is the more appropriate 
because the turbine was invented in the first instance for the express 
_ purpose of driving a dynamo. Parsons realized, in the early eighties, 
_ that the generating of electricity gave steam a new job to do, a job that 
_ needed high-speed rotation, a job for which reciprocating movement was 
_ out of place. So he invented the turbine, in which high-speed rotation 
_ was a fundamental feature, and he invented also a high-speed dynamo 
suitable for it to drive, and he patented them both on the same day in 
_ April, 1884. The dynamo, he used to say, gave him as much trouble 
_ as the turbine. In all the early turbine-driven dynamos it was the 
armature that was caused to revolve in a gap between the poles of a 
stationary field-magnet. But later, when a demand came for much 
_ greater power and much higher electric potential the parts were inverted : 
the field-magnet was caused to revolve, and thereby to generate alternating 
_ currents of high potential—often many thousand volts—in a surrounding 
stator which was made up of highly-insulated coils. 
_ The commanding position of the steam turbine is, of course, mainly 
_ due to its high thermodynamic efficiency : in large sizes it gets more work 
out of coal than can be got in any other way. But apart from that, its 
avoidance of reciprocation gives it an advantage which only those who 
_ Yemember early power stations with their piston engines can fully realise. 
_ Again, it can readily be built and run in big units, and another merit 
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