So far all the trials had been made with two crank engines; so it was now decided to construct another set of engines for 150 lb. pressure, having a crank to each cylinder.  These engines had cylinders 201/2 inches, 33 inches, and 58 inches diameter by 36 inches stroke, and were fitted into the screw steamer Rosario, whose dimensions are 275 feet 3 inches between perpendiculars, 34 feet 3 inches beam, and 19 feet 2 inches depth of hold, 1,862 tons gross, and the deadweight capacity 2,550 tons.  In March last year she was loaded with 2,530 tons deadweight, and did the voyage to Bombay at an average speed of 8.6 knots on a consumption of 10.5 tons per day of South Yorkshire coal, and burnt on the voyage 347 tons.  This result is superior to that of the Draco when the size of the ship is taken into account, but is not so much so as might have been anticipated from the increase of pressure and the rate of expansion, which was 14.4 in the Rosario and 12 in the Draco.  Another set of 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