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STEAMER HI An interesting feature in the machinery of this ship is found in the system of hot draft in use thereon, and the following table is a resume of the data of this feature for each test, and also for a special test with the fan shut off, and with the fan running at different rates of speed: Revolu- TEMPERATURES. A k Pressure. - S Retarders. tions of fan. 431 £"3 Furnace. Uptake. Fan. Furn/ce. .4 Uptake. 1 Out 273 597 2.9 X o Out 420 223 622 2.77 .41 .2125 r> In 418 182.5 470 2.75 .52 8 4 In 4(30 189 520 3.2 _7 v% 5 In 431 18? 487 2.88 .oo _5 6 In 415 186 471 2.7 .52 A / Out 0 0 425 0 .0 H / Out 467 237 570 3.4 .75 3. 7 Out 427 238 560 2.8 .55 3_ / Out 382 238 545 2.2 .45 8 During the fifteen minutes that the fan was stopped, and the attempt was made to run with natural draft, with the ash pit doors open, the steam pressure dropped from 155 to 120 pounds, and in twenty minutes from the time the fan was started again, the gage was back to 155 pounds. The air supplying the fan was drawn through the engine room and mostly through the skylight immediately above the cylinders, and to this may possibly be attributed the fact that it was impossible to get indicator cards from the H.P. cylinder without the interference of water in the indicator. A noticeable feature was the efficiency of the condenser and air pump, and by which, when running at half speed, a vacuum of 28 inches could be obtained, and 26 inches at full speed, and a good vacuum could be maintained after the engines were stopped, rendering them easy of manipulation in port. Before leaving the lower port for this trip, 163| net tons of freshly mined "lessen" lump coal, from near Pittsburgh, Pa., was put aboard for fuel, and the total consumption for the round trip was not over 168 tons. EY H. BROWN. 59 The amount of ashes in the coal, deduced from several tests, was 11 per cent of the coal. The water supply of the feed-water heater was taken from the sea cock, and its temperature raised about 100°; but were the piping soar-ranged that the supply could have been taken from the hot well, the temperature of which was only 6 or 7° below that of the feed-water, the temperature of the feed-water could have been made 30° higher than it was. It was desirable to make a test with the main engines only on the main boilers, the auxiliaries taking their supply from the donkey boiler. This failed for lack of sufficient steam from the donkey boiler, and it was also rendered impossible, by the manner of piping, to take steam for any one auxilliary from this source, without shutting all the others from the main boilers. At the time of the only opportunity for testing the auxil-liaries separate from the main engines, the fan was undergoing repairs and the fires in the furnace banked, but it is seriously questioned whether running such a light load on such a large boiler would not have made the apparent cost of the power excessive under these circumstances. On account of the short duration of test No. 4, the results concerning the consumption of coal can not be considered strictly reliable. The test was concluded earlier thau we anticipated at the outset, at the request of the officers of the ship, since the extra power and speed caused an objectionable vibration of the ship; similar vibrations of the same period, seventy-eight per minute, were also noticed in passing through water about six fathoms deep. In more shallow water or in deeper water this was not the case. The method of making the coal tests was to start on weighed coal after the fires had been cleaned, noting the time of putting the first shovelful of the weighed coal on the fires, for the beginning of the test, continuing the firing of weighed coal as long as desirable, and then noting the time of putting on the first shovelful of the unweighed coal, for the end of the test. Fires were cleaned every six hours and the tests generally ran through one cleaning. The assistance in making observations and weighing coal, furnished by three men engaged for that purpose, was most satisfactory, and th