Scientific American Supplement, No. 312, December 24, 1881 | Page 3

the ground wheels. This arrangement was adopted
because the crane has to travel up a gradient of 1 in 30, and the bogies
enable it to take the incline better; they also distribute the weight more
evenly on the wheels. The gauge of the rails is 15 ft, the wheels are 2 ft.
6 in. in diameter, and have heavy steel tires. The weight on each of the
front wheels when running with the ballast, but no load, is about 16
tons. A powerful brake is applied to the wheels when descending the
incline.
All the clutch levers, break treadle, and handles are brought together, so
that one man has the crane under his entire control. An iron house, of
which the framing only is shown, extends from the gearing right back
to the boiler, forming a most spacious engine room and stokehole. A
separate donkey engine is provided for feeding the boiler. The truck is
furnished with legs under which packings can be wedged so as to
relieve the load on the wheels when block-setting. The slings seen
under the boiler are for hanging a concrete balance weight; this will
weigh about 20 tons. The weight of the crane itself without load or
ballast is about 80 tons. The crane was tested under steam with a load
of 19 tons with the most satisfactory results; the whole machine
appeared to be very rigid, an end often very difficult to obtain with
portable wrought-iron structures and live loads. The result in the

present case is probably greatly due to the careful workmanship, and to
the fact that the sides and ends of the plates are 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.
* * * * *

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.]
* * * * *

THE ELEVATED RAILWAYS OF NEW YORK.
But few persons who have not been in New York since the construction
of the elevated roads, and witnessed their equipments and operations,
can have any adequate idea of the extent of them, and of the people,
machinery, and appurtenances required in working them. A recent
inventory discloses the fact that there are 32 miles of roadway, 161
stations, 203 engines, and 612 cars, while 3,480 trains a day are run.
There are 3,274 men employed on these roads, 309 of whom are
engineers, 258 ticket agents, 231 conductors, 308 firemen, 395 guards
or brakemen, 347 gatemen, 4 road inspectors, 106 porters, 33
carpenters, 27 painters, 69 car inspectors,