igh tension before the
boiler is put in actual use. It is, I hope, rapidly becoming a thing
of the past.

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