G.—ENGINEERING. 115 
Returning to sea-going vessels, the Propontis, a vessel built in 1864, 
was re-engined at Fairfield with triple-expansion three-crank engines 
_ designed by the late Dr. Kirk in 1874, with boilers working at 150-lb. 
pressure ; but the boilers, Rowan’s water-tube, proved unsatisfactory, and 
in 1876 new Scotch boilers of 90-lb. pressure were fitted. The first really 
successful triple-expansion three-crank job, the Aberdeen, was built in 
1880 by Robert Napier & Sons, and fitted with engines and 125-lb. 
pressure boilers designed by Dr. Kirk. The re-engining of the Propontis,' 
however, marked the opening of a new era, which only developed slowly 
at first, due in some measure to the then rules for the thickness of the 
boiler shells and furnaces. In 1883 the late Mr. Walter Brock designed 
and fitted two-crank four-cylinder tandem triple-expansion engines to the 
sister ships Arawa and Tainui, for the London-New Zealand service. 
They had high and intermediate on the top with two low-pressure cylinders 
of equal diameter below, the working pressure being 160 1b. The Board 
of Trade Surveyors were naturally cautious in the use of mild steel in 
boilers, then a comparatively new material, but they had been gaining 
confidence in it and had also made interesting experiments on two kinds 
of furnace flues, to ascertain their resistance to collapsing under hydraulic 
pressure. The two kinds were Fox’s corrugated furnaces, and plain ones 
with widely spaced flanged rings, called at that time coxcomb furnaces. 
Under these circumstances and after full discussion the 160-lb. pressure 
desired by Mr. Brock was made possible by agreement as to shell thickness 
between the Board’s Surveyors and the Engineer ; Fox’s steel corrugated 
furnaces were used. These vessels showed excellent economy and proved 
thoroughly reliable. Thereafter quadruple-expansion engines using 
_ pressures of 180 lb., 200 lb., or even higher, became common, with improved 
- economy in fuel, but the lower limit of pressure at the condenser was still 
little altered. 
The next great step was the introduction of the Parsons turbine. My 
_ first connection with the Parsons turbine was in 1890, when a small one 
_ driving an electric dynamo was fitted on board of the Duchess of Hamilton, 
on the Clyde. It was a tiny plant, the turbine driving the dynamo 
direct at 10,000 revolutions, and was not very economical, but as it was 
only rarely used, on evening cruises, that did not matter much. It was, 
however, a forerunner of that great invention, permitting the economical 
use of the low end of the pressure curve which could not be efficiently 
used in the reciprocating engine, thus improving the economy of the steam- 
engine, apart altogether from the other advantages of freedom from vibra- 
tion troubles and the increased speed of ship which could be obtained 
through its light weight per I.H.P. 
None can forget the tremendous interest created by the appearance 
of the 34}-knot 100-ft. Turbinia, at Spithead Review in 1897. I felt 
that here was the engine we had been looking for to use in fast cross- 
Channel work, and it was a great gratification when Sir Charles Parsons 
and Captain John Williamson arranged with my firm that we should join 
‘Ma venture to build and run a Clyde river-steamer fitted with turbines ; 
__! Messrs. Normand, of Havre, now inform me that in 1871 Benjamin Normand fitted 
a triple-expansion engine ina passenger steamer on the Seine, and that before 1880 he 
had so fitted twelve vessels successfully. They also state that M. Normand fitted his 
first compound engine at the same time as John Elder’s ‘ Brandon.’—18/9/25. 
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