With a proper proportion of diameter and pitch of rivet, all that is required is the use of a light “fuller tool” or the round-nosed tool used in what is known to the trade as the “Connery system.”

There is but little need of calking if means are taken to secure a clean metal-to-metal face at the joint surfaces.  When the plates are put together in ordinary course of manufacture, a portion of the mill scale is left on, and this is reduced to powder or shaken loose in the course of riveting and left between the plates, thus offering a tempting opening for the steam to work through, and is really cause of the heavy calking that puts so unnecessary a pressure on both plate and rivet.  A clean metallic joint can be secured by passing over the two surfaces a sponge wet with a weak solution of sal-ammoniac and hot water, an operation certainly cheap enough both as to materials and labor required.

[Illustration:  FIG. 19]

The above cut, Fig. 19, gives an illustration of calking done by sharp-nosed and round nosed tools, respectively.  It will be seen by Fig. 20 that the effect of a round-nosed tool is to divide the plate calked, and as the part divided is well driven toward the rivets, a bearing is formed at a, from one-half to three-fourths of an inch, which increases the strength of joint, and will in no way cut or injure the surface of the under plate.  A perfect joint is thus secured.

[Illustration:  Fig. 20.]

* * * * *

THE NEW BRITISH BATTLE SHIP EMPRESS OF INDIA.

The launching of this first-class battle ship was successfully carried out at Pembroke Dockyard on May 7.  She is the second of a class of eight battle ships built and building under the Naval Defense Act of 1889, which were specially designed to take part in general fleet actions in European waters.  The leading dimensions are:  Length, between perpendiculars, 380 ft.; breadth, extreme, 75 ft.; mean draught of water, 27 ft. 6 in.; and displacement at this draught, 14,150 tons, which surpasses that of any other ship in the navies of the world.  Previous to the launching of the Royal Sovereign—­a sister vessel—­which took place at Portsmouth in February last, the largest war ships in the British navy were the Nile and Trafalgar, each of 12,500 tons, and these were largely exceeded in displacement by the Italia, of 13,900 tons, and the Lepanto, of 13,550 tons, belonging to the Italian navy.

The Empress of India is built throughout of mild steel, the stem and stern post, together with the shaft brackets, being of cast steel.  Steel faced armor, having a maximum thickness of 18 in., extends along the sides for 250 ft. amidships, the lower edge of the belt being 5 ft. 6 in. below the normal water line.  The belt is terminated at the fore and after ends by transverse armored bulkheads, over which is built a 3 in. protective