planed throughout, so that the webs of the girders get a fair bearing
on the top and bottom plates.

The crane showed itself to be very handy and quick in working, the
speeds with 19 tons load, as actually timed at the trial, are: lifting
16 ft. per minute, racking motion 46 ft. per minute, slewing through a
complete circle 90 ft. diameter, four minutes, equivalent to a speed
at load of 60 ft. per minute. The crane was constructed by Messrs.
Stothert & Pitt, of Bath, to the order of the Crown agents for the
colonies, and we understand that the design and construction have
given complete satisfaction to Sir J. Coode, the engineer to the
harbor works, under whose supervision the crane was
constructed.--_Engineering._

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IMPROVED STEAM-BOILER.

An improvement in steam-boilers, best understood by reference to the
ordinary vertical form, has been introduced by Mr. T. Moy, London.
Here the flue is central, and, as shown in the accompanying
illustration, is crossed by a number of horizontal water-tubes at
different heights. The ends of these tubes are embraced, within the
steam chamber, by annular troughs. At the top domed part of the boiler
are two annular chambers, the outer one being intended to receive the
water upon entry from the feed-pump, and to contain any sedimentary
deposit which may be formed. The water next passes, by the pipe, _a_,
in the figure, into the inner chamber, surrounding the end of the
uptake flue, whence it flows through the pipe, _b_, down into the
first of the annular troughs above mentioned, and afterward overflows
these troughs in succession until it reaches the bottom. Mr. Moy
claims to have secured by this means a boiler of quick steaming
capacity, together with a reduction in the weight of metal, and
considerable economy of fuel. By the arrangement of the water in a
number of shallow layers a large steaming surface is obtained, and
there is a good steam space rendered available round the troughs. The
water also enters at a point where it may abstract as much heat as
possible from the furnace gases before they escape; and by the
separation of the top domed chamber from the rest of the boiler the
operation of scaling and cleaning is facilitated. The arrangement is
also adapted to horizontal and multitubular boilers, to be fired with
solid, liquid, or gaseous fuel.

[Illustration: IMPROVED BOILER.]

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