TRIAL OF A TORPEDO BOAT.

(SYDNEY EVENING NEWS, APRIL 2.) Vest rday forenoon there was another trial in the harbor of the torpedo boat Acheron. This wonderful craft, it will be remembered, was bult to the order of the Government by the tlas Company, Darling Harbor, on plans prepared by Mr Norman Selfe, and the trials yesterday, though in no way demanded by contract stipulations, were decided upon a" final, and prior to her passing from the builders' hands. With the engineers and one deck hand, there were altogether thirteen persons on board, ten above the ordinary number, and this, with two extra tons of water in the tanks, added at least 10 per cent on the total weight of the boat, and was reckoned to make a difference of at least one knot in the speed. The little steamer let her moorings in Darling Harbor j iat upon 11 o'clock, aad steered round Miller's Point and towards Port Denisor. Even at ha f-speed she ran past the fastest steam launches and ferry boats, the passengers aboard which gazed upon her with evident bewilderment. After passing Fort Macquarie the order " full speed" was given, and the little craft nearly jumped out of the water. Tbe equilibrium of the unwary was 'mmpdiately disturbed, and the vessel, now vmshed on by 200 horse-piwer, darted through tho wat -r like a fiah . The wind was rjuht ahead, and the water lumpy, but the ve^-el passed through rough and Bmooth alike, taking ahourd occasionally a little of the damp element for t c entectamment of tin principal elect ician T>e measured mile between Pinchgut and Bradley's Head was run in 4 36. This was not satisfactory. Twice tbe engines had to be lowered owing to some oversight below, and the vessel was fetched ! ack. In the next trial the engineers we- c better prepared, and she did a nde in the trifle under four minutes thirteen seconds. This meant 17 miles an hour, the average of our railway trains, and the wonderful result was accomplished against a strong head wind, acd a heavy handicap in the shape of extra weight. As no alteration of propeller, expected to secure an average of two knots, had been made, the trial was considered very satisfactory. n< he trials over the mile were afterwards repeated, with varying but most satisfactory results. Considerable surprise was exoresaed at the statement that tho Acheron cost LBOO or L9OO less than Thorneycroft's celebrated torpedo boats, whose speed is but a trifle above that which the Sydney built vessel attained yesterday.The Acheron, it may again be mentioned, ii 80ft long, 10ft beam ; has surface condensing engines llin and 19in diameter and 14in stroke ; the pressure on trial was 2001 b ; the vacuum, 264 '< at »d the revelations 280 to 300. With further experience it h expected that 350 revolutions will be obtained.