A small torpedo boat built for the Russian Government by Messrs. Yarrow, in 1879, was considered to be the most formidable vessel of her class afloat. Her speed was 22 knots, and on 10 tons of coal it was estimated that she would be able to steam 800 miles at a speed of 10 to 12 knots. Her stem was formed to be a sharp ram, and from the conning tower to the stem she had a hood over her deck to throw off the water she might take over her bows. The two launching tubes for her Whitehead torpedoes were on either side of the bows. The theory was that the first torpedo should break through the nets or other guards, and that the second torpedo, discharged a few seconds later, should pass through the gap thus made in the ship’s defence and attack the hull itself. A comparatively recent invention is a contrivance to be carried on the nose of the torpedo to cut through the net. Torpedo boats had to have their “parent ship,” or ship to which they could go for any repairs to be made when at sea. The parent ship was necessarily a floating torpedo boat factory, and, if the torpedo boat were not too large, could hoist her on board and repair her as effectually as if she were in dry dock or on the slips ashore, and lower her again to the water when the work was finished. The _Vulcan_, of 6,620 tons displacement, was launched in 1889 to undertake these duties, and also act as a laboratory in connection with the mining service. She had two powerful hydraulic cranes for hoisting in and out torpedo boats, of which she carried six on her deck for the assistance of the fleet she might accompany, and also had two counterbalancing barges and steam pinnaces. In order that she might be able to protect herself she was equipped with twenty quick-firing guns. Several “parents” or floating repair ships have been added to the Navy of recent years, and every one of them is as modern as science and money can make her. Having a large fleet of cruisers and battleships, it has been the British policy of late years to arm them with a powerful secondary battery, especially designed to meet torpedo attack. It is not touching upon international or diplomatic questions to state that the very preponderance of the British fleet has rendered the risk of invasion of these islands exceedingly small, and the resources of this country have been, and are, so vast, that the much-debated two-power standard--in spite of the numerous and contradictory estimates of comparative naval strength based upon it--has, on the whole, been maintained. If the theoretical British frontier be the coast-line of a possible opponent, it is evident that vessels which can steam to an enemy’s coasts and destroy his torpedo boats there are of greater use than the torpedo boats which can only operate along the coast-line, or venture to cross the seas in fine weather. This has been set forth as one reason why the British Admiralty of recent years has preferred destroyers to the smaller vessels.