The automobile or, as it was then called, the “submarine locomotive” torpedo was now a practicable, though by no means perfected, weapon, and the Austrian naval authorities gave it a thorough trial at Fiume in 1868. Whitehead rigged up a crude ejecting tube on the bow of a gunboat, and successfully discharged two of his torpedoes at a yacht. The Austrian government promptly adopted the weapon, but could not obtain a monopoly of it, for Whitehead was a patriotic Englishman. The British admiralty invited him to England two years later, and after careful trials of its own, induced the English government to buy Whitehead’s secret and manufacturing rights for $45,000. Other nations soon added “Whiteheads” to their navies, and in 1873 there was built in Norway a large, fast steam launch for the express purpose of carrying torpedoes and discharging them at an enemy. Every one began to build larger and swifter launches, till they evolved the torpedo-boat and the destroyer of to-day. The torpedo itself has undergone a similar development in size and efficiency. The difference between the Whiteheads of forty-five years ago and those of to-day is strikingly shown in the following table: BRITISH NAVAL TORPEDOES OF 1870 _Length, _Diameter, _Charge, _Range, _Speed, Feet_ Inches_ Pounds_ Yards_ Knots_ Large 14 16 67 600 7.5 guncotton Small 13 10.58 in. 14 18 200 8.5 dynamite BRITISH NAVAL TORPEDOES OF 1915 Large 21 21 330 12,000 48 guncotton Small 18 18 200 16,000 36 guncotton The length of a large modern torpedo, it will be observed, is only three inches less than that of Fulton’s famous submarine boat of 1801. A Whitehead torpedo is really a small automatic submarine, steered and controlled by the most ingenious and sensitive machinery, as surely as if it were manned by a crew of Lilliputian seamen. Projecting from the head is the “striker,” a rod which, when the torpedo runs into anything hard, is driven back in against a detonator or “percussion-cap” of fulminate of mercury. Just as the hammer of a toy “cap-pistol” explodes a paper cap, so the sudden shock of the in-driven striker explodes the fulminate, which is instantly expanded to more than two thousand times its former size. This, in turn, gives a severe blow to the surrounding “primer” of dry guncotton. The primer is exploded, and by its own expansion sets off the main charge of several hundred pounds of wet guncotton.