G.—ENGINEERING. 125 
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them a storage battery of Faure’s cells, the advent of which had been 
hailed with enthusiasm and had raised unduly high hopes. For prime- 
mover he chose the new gas-engine of Dugald Clerk which completed its 
cycle in two strokes, unlike the already familiar Otto engine, which required 
four. Clerk’s engine was itself a novelty the importance of which we 
have come to recognise. To this day all internal-combustion engines 
use either the Clerk or the Otto cycle, and for large powers the Clerk 
_ eycle has advantages which tend to give it the favoured place. 
___ Fifty years ago the gas-engine was much in the public eye. It had 
already proved its value in many workrooms. There was still no supply 
| of electricity from public stations, and for a private installation the gas- 
engine furnished a suitable and exceedingly convenient source of power. 
Tt was a day of small things; an engine which developed as much as 
_ 20 horse-power was described as a ‘king of gas-engines.’ Within this 
~ modest limit the Otto engine, which dates from 1876, had a well-deserved 
reputation as an efficient and trustworthy prime-mover that would run with 
; little attention, using ordinary town gas as its fuel. At the Jubilee meeting 
_ of this Association Emerson Dowson drew attention to a less costly alterna- 
_ tive: he had made what was called producer gas from coke or anthracite, 
_ and had run engines withit. He had even demonstrated that with Dowson 
gas you could get a horse-power from 1 lb. of coal per hour, instead of 
burning 2 or 3 lbs. at the very least, as you had to do in a steam-engine. 
From this it was clear that the gas-engine offered immensely attractive 
possibilities as a generator of power. 
Even before 1881 engineers were busy with efforts to improve its 
efficiency. Fleeming Jenkin, my teacher and professional chief, was 
struggling to apply to it the regenerative methods of economising heat 
which Stirling originated in his air-engine a century ago—methods which in 
the meantime had revolutionised other industries, notably the manufacture 
of steel. No engineer who gave the matter serious thought could fail to see 
_ the advantage of having heat developed within the working substance itself 
instead of being conveyed to it by conduction through a containing shell ; 
it was, in fact, the failure of the containing shell that ruined Stirling’s 
engine. Another obvious merit of internal combustion was one that Carnot 
_had recognised in the immortal little treatise where he laid the foundations 
of thermodynamics—the advantage, namely which you secure by supplying 
heat to the working substance at a much higher level of temperature than 
can be reached with steam. Finally, there was this broad difference : 
the gas-engine had the indefinite promise of youth ; the steam-engine was 
an old servant whose limitations were well known. Nobody expected 
that steam would change its ways. Small wonder then, that the engineers 
pet those days looked to the future of the gas-engine with exaggerated 
hope. 
It was in that spirit that Bramwell made the prophecy we have now, 
_ after fifty years, to review. The occasion—as I have said—was the Jubilee 
_ Bastion of this Association, held at York in 1881. The President of 
Section G was Sir William (afterwards Lord) Armstrong. His address 
was mainly on other subjects, but incidentally it contains an exceedingly 
"apt criticism of the steam-engine as they knew it then. He said: ‘In 
_ expanding the steam we quickly arrive at a point at which the reduced 
