| Year. | Name of vessel. | Diameters of cylinders Inches. | Length of Stroke. Inches. | Indicated horsepower |
| 1881 | Alaska | 68, 100, 100 | 72 | 10,686 |
| 1881 | City of Rome | 46, 86; 46, 86; 46, 86 | 72 | 11,800 |
| 1881 | Servia | 72, 100, 100 | 78 | 10,300 |
| 1881 | Livadia yacht | 60, 78, 78; 60, 78,78; 60, 78, 78 | 39 | 12,500 |
| 1883 | Oregon | 70, 104, 104 | 72 | 13,300 |
| 1884 1884 | Umbria Etruria | 71, 105, 105 | 72 | 14,320 |
| 1888 1889 | City of New York City of Paris | 45, 71, 113; 45, 71, 113 | 60 | 20,000 about |
| 1889 1889 | Majestic Teutonic | 43, 68, 110; 43, 68, 110 | 60 | 18,000 |
In war vessels the increase has been equally marked. In 1881 the maximum power seems to have been in the Inflexible, namely, 8,485 indicated horse-power. The following will give an idea of the recent advance made: Howe (Admiral class), 11,600 indicated horse-power; Italia and Lepanto, 19,000 indicated horse-power; Re Umberto, 19,000 indicated horse-power; Blake and Blenheim (building), 18,000 indicated horse-power; Sardegna (building), 22,800 indicated horse-power. It is thus evident that there are vessels at work to-day having about three times the maximum power of any before 1881.
General Conclusions.--The progress made during the last ten years having been sketched out, however roughly, the general conclusions may be stated briefly as follows: First, the working pressure has been about doubled. Second, the increase of working pressure and other improvements have brought with them their equivalent in economy of coal, which is about 20 per cent. Third, marked progress has been made in the direction of dimension, more than twice the power having been put into individual vessels. Fourth, substantial advance has been made in the scientific principles of engineering. It only remains for the writer to thank the various friends who have so kindly furnished him with data for some of the tables which have been given; and to express the hope that the next ten years may be marked by such progress as has been witnessed in the past. But it must be remembered that, if future progress be equal in merit or ratio, it may well be less in quantity, because advance becomes more difficult of achievement as perfection is more nearly approached.
Paper read before the Institution of Mechanical Engineers, July 28, 1891.
Transactions Northeast Coast Institution of Engineers and Shipbuilders, vol. 7, 1890-91, p. 179.