SECTION G.—ENGINEERING. 
FIFTY YEARS’ EVOLUTION IN NAVAL 
ARCHITECTURE AND MARINE 
ENGINEERING. 
ADDRESS BY 
Sir ARCHIBALD DENNY, Barr., F.R.S.E., LL.D., 
PRESIDENT OF THE SECTION. 
Tuts Section of the British Association covers the whole vast field of 
Engineering, but I propose to limit my survey to accord with the title I 
have chosen. No one could within the limits of such an address cover the 
whole field, nor, indeed, could an engineer of any section cover all the 
ground in that one, for within every branch of engineering specialisation 
has rapidly developed. I can do no more then than note the milestones on 
the fifty-year road and the landmarks, and must deny myself the pleasure 
and resist the temptation of straying down side-roads, pausing only on 
the main-road to admire the changing landscape. 
Let us start with Marine Engineering, where the evolution has been 
positive and fairly well defined. After Watt’s invention of the separate 
condenser, many years elapsed before the next considerable step—the 
introduction of the compound steam-engine. This was natural, as steam 
pressures were too low to make compounding profitable. The first record 
I can find of compounding was John Elder’s ‘ Brandon ’ in 1854, and pro- 
gress thereafter was not very rapid; but when I began my apprenticeship, 
in 1876, the old box boiler had been replaced by the now highly appreciated 
Scotch circular return-tube boiler, supplying steam to two-cylinder 
compound engines at about 60-lb. pressure. It was not then found profit- 
able to carry more than about 25 in. of vacuum. Auxiliary machinery 
was almost non-existent ; the circulating, air, bilge, sanitary and feed — 
pumps were worked off the main engine, with a crank and fly-wheel 
stand-by feed-pump, and perhaps a similar pump for sanitary and bilge © 
purposes, and when a double bottom was fitted (which was not always) a 
similar pump for ballast tanks. That was the equipment of a good-class 
engine-room in those days. On deck the steering gear was usually — 
fitted near the bridge and connected to the quadrant or tiller by chains © 
and rods laid in the gutter-waterways, with numerous turns and kinks, ~ 
whilst a combined windlass and capstan on the forecastle head, and winches — 
of the simplest type at the hatches, completed the deck machinery. There — 
might, in addition, be a clattering steam ash-hoist fitted in one of the 
stokehold ventilators. ( 
As to types of marine engines—in the Navy, for protection reasons, — 
horizontal machinery was not uncommon, while in the mercantile marine, 
for screw ships, the vertical type was practically universal. In paddle- 
steamers for river and coast service, of which there were many, the beauti- 
ful oscillating engine, which had the advantage of taking up little room 
lengthwise, was still built; but the diagonal engine was more common, 
either with single cylinder and haystack boiler or compound two-cylinder. 
