No one doubts the ability of our shipbuilding yards to turn out these monsters; and on the measured mile, and for a good long distance, we shall certainly see the contract speeds attained and some excelled.  But the whole difficulty turns on the question of the coal capacity, and whether it is sufficient to last for even five days or for 3,000 miles.  Every effort then must be made to shorten the length of the voyage from port to port; and we may yet see Galway and Halifax, only 2,200 miles apart, once more mentioned as the starting points of the voyage as of old, in the earliest days of steam navigation.  In those days the question of fuel supply was a difficulty, even at the then slow speeds, in consequence of the wasteful character of the engines, burning from 7 lb. of coal and upward per horse power hour.  Dr. Lardner’s calculations, based upon the average performance of those days, justified him in saying that steam navigation could not pay—­as was really the case until the introduction of the compound engine.

It is recorded in Admiral Preble’s “Origin and Development of Steam Navigation,” Philadelphia, 1883, page 160, that the Sirius, 700 tons and 320 horse power, on her return voyage had to burn up all that old be spared on board, and took seventeen days to reach Falmouth.  An interesting old book to consult now is Atherton’s “Tables of Steamship Capacity,” 1854, based as they are upon the performance of the marine engine of the day.  Atherton calculates that a 10,000 ton vessel could at 20 knots carry only 204 tons of cargo 1,676 miles, while a 5,000 ton vessel at 18 knots on a voyage of 3,000 miles could carry no cargo at all.  Also that the cost per ton of cargo at 16 knots would be twenty times the cost at eight knots, implying a coal consumption reaching to 12 lb. per horse power hour.  It is quite possible that some invention is still latent which will enable us to go considerably below the present average consumption of 2 lb. to 11/2 lb. per horse power hour; but at present our rate of progress appears asymptotic to a definite limit.

To conclude, the whole difficulty is one of fuel supply, and it is useless to employ a fast torpedo boat as our model, except at the speed at which the torpedo boat can carry her own fuel to cross the Atlantic.  If the voyage must be reduced in time, let it be reduced from six days to four, by running between Galway and Halifax, a problem not too extravagant in its demands for modern engineering capabilities.  A statement has recently gained a certain amount of circulation to the effect that the Inman Company was about to use petroleum as fuel, in order to obtain more steam.  We have the best possible authority for saying there is not the least syllable of truth in this rumor.  It has also been stated that since solid piston valves have been fitted to the Teutonic in lieu of the original spring ring valves, she has steamed faster.  This rumor is only partially true.  Her record, outward passage, of 5 days 16 hours 31 minutes, was made on her previous voyage.  She has, however, since made her three fastest trips homeward.—­The Engineer.