engines was made from
the patterns of those of the Draco, but with the high pressure cylinder
20 inches diameter, steam at 150 lb. pressure being supplied from two
single ended boilers, having a total heating surface of 2,200 square
feet. They are fitted in the S.S. Finland, a cargo boat 270 feet long, 35
feet beam, by 18 feet depth of hold, and 1,954 tons gross register. In
January she was loaded with 2,500 tons deadweight, and sailed for
Rangoon. The average speed attained was 8.42 knots per hour, or 202 miles
per day, on a consumption of 10.3 tons of Welsh coal per day, the rate of
expansion being 12. It should be mentioned that all these ships named are
fitted and steered with steam stearing gear, so that in comparing these
results and those published of the engines made by an eminent engineer in
the north of England, an allowance should be made, as in that ship there
was no steam stearing gear.

I have chosen to make all these comparisons by reference to the ships'
logs, and to give results such as a shipowner looks for rather than those
which engineers prefer to use in forming a judgment on the merits of
different engines. I do this for two reasons: first, because the
commercial success of the triple compound engine depends on the saving it
can effect in a long voyage; and secondly, because I had no reliable
indicator diagrams from which the consumption per indicated horse power
could be calculated with any degree of accuracy. On trial trips with the
steamers already named, the consumption of ordinary South Yorkshire coal
was 1.6 lb. per indicated horse power, and the consumption of water per
indicated horse power calculated from the high pressure indicator
diagrams was 1.41 in the Draco, 13.2 in the Rosario, and 13.16 with the
Finland, or taking the medium pressure diagrams, it was 12.2, 1.30, and
11.95 respectively. Twelve months ago we constructed for Messrs. Thomas
Wilson, Sons & Co., two sets of triple expansion engines of 600 indicated
horse power, one having two cranks and the other three cranks, the
engines, boilers, and propellers being otherwise exactly alike and fitted
into sister ships. The water consumed in the three crank engine is 12.93
lb., against 13.0 in the two crank, but the former drives its ship nearly
1/2 knot per hour faster than the latter does its, and when both ships are
driven at the same speed the consumption of coal in the three crank ship
is considerably less than in the other.

We