The navies of Europe, including the British navy, have undergone of late considerable expansion in respect of their very fast unarmored steel vessels, the designing and successful construction of which have been brought about by improvements in the quality of ship steel and in steam-machinery, notably as regards the latter, by the employment of “forced draught.”[27] These are called torpedo-vessels, as distinct from torpedo-boats. There are in process of completion for the British navy eight of 1630 tons (the _Archer_ class), each carrying six 6-inch 5-ton guns, and estimated to steam with forced draught from 16 to 17 knots; two of 1430 tons each (_Scout_ class), carrying four 5-inch 2-ton guns, with an estimated maximum speed of 16 knots; and two of 785 tons (_Curlew_ class), called “gun and torpedo” vessels; speed, 15 knots; armament, one 6-inch 89-cwt. and three 5-inch 36-cwt. guns. There is also a class of “torpedo gun-boats” (the official designation, but not one which expresses any very manifest distinction from the last-named class), which are of a very notable character. This (the _Grasshopper_) class, of which each vessel is of only 450 tons displacement, is to be supplied with engines of 2700 indicated horse-power. The diagrams on page 90 exhibit the general form and particulars of these very remarkable little vessels, which are expected to steam at fully 19 knots (22 miles) per hour. Against the above torpedo-vessels of the British navy are to be set, in the French navy, four torpedo-cruisers of 1280 tons, 17 knots speed, carrying each five 4-inch guns; and eight torpedo despatch-vessels, each of 320 tons, and designed to steam at 18 knots, carrying machine guns only; such machine guns being also carried, of course, by all the fast torpedo-vessels and gun-boats, both French and English, previously referred to, but in their cases in conjunction with their other guns. These 320-ton torpedo-vessels of France are to be driven by machinery of 1800 indicated horse-power. [Illustration: BRITISH TORPEDO GUN-BOAT OF THE “GRASSHOPPER” CLASS (SIDE VIEW).] [Illustration: THE “GRASSHOPPER”—PLAN OF UPPER DECK, POOP, AND FORECASTLE.]