Scientific American Supplement, No. 611, September 17, 1887 | Page 3

which receives the crank pin of variable
position is fixed directly upon the axle, d, of the same flywheel carried
by the support, D; but when the motor can be applied directly, as is the
case for example in the Singer sewing machine, upon the axle of the
machine, no support is used, and the arrangement shown in Figs. 3 and
4 is adopted. In this case the disk, F', is cast with three arms which
serve, by means of a screw, to fasten it to the flywheel carried by the
axle of the sewing machine.
When the motor is used on the upper stories of buildings, the changes
of speed incidental to drawing the water from the lower stories from the
same pipe can be compensated by the use of an accumulator. This
accessory apparatus is composed of a reservoir of a capacity of 10 liters
or more, intercalated in the pipe which supplies the motor, so that the
water coming from the principal pipe enters the bottom of this reservoir,
passing through an India rubber valve opening inward, the supply for
the motor coming through a tube always open and placed above this
valve. The air trapped in the accumulator is compressed by the water,
and when the pressure in the pipe decreases, the valve closes and the
compressed air drives the water through the motor with decreasing
pressure until normal pressure is re-established in the
pipes.--_Publication Industrielle._
* * * * *

TRIAL TRIP OF THE OHIO.
Some important trials of the new machinery of the screw steamer Ohio,
belonging to the International Navigation Company, have recently
taken place on the Clyde. The Ohio is an American built steamer
measuring 343 ft. by 43 ft. by 34 ft. 6 in., and of 3,325 tons gross. She
has been entirely refitted with new engines and boilers by Messrs.

James Howden & Co., Glasgow, who also rearranged the bunker,
machinery, and hold spaces, so as to give the important advantage of
increased cargo accommodation obtainable from the use of their
improved machinery, which occupies considerably less space than the
engines and boilers of the same power which have been replaced. The
new engines are of the triple expansion type, and the boilers, which are
designed for supplying steam of 150 lb. pressure, are worked on
Howden's system of forced draught, which combines increased power
with high economy in fuel. The object of the owners in refitting the
Ohio was to test the capability and economy of this system of forced
draught on a sufficient scale to guide them in dealing with steamships
of the largest class and great power.
In the refit of the Ohio the boilers were designed to work with a very
moderate air pressure, this being sufficient for the power required by
the contract. The combined power and economy, however, guaranteed
by Messrs. Howden & Co. for the use of their system of forced draught
was higher than has hitherto been attempted in any steamship, and
sufficient, if attained, to prove the large reduction that could safely be
made in the number and size of boilers for the use of the system, and
the quantity of coal required to produce a given power. The contract for
the refit of the steamer required that 2,100 indicated horse power
(which was the maximum power of the engines removed) should be
maintained during the trial on a consumption of 1.25 lb. of coal per
indicated horse power per hour. Originally the boilers of the Ohio, from
which this power was produced, were three in number, double ended,
12 ft. 6 in. in diameter by 17 ft. 6 in. in length, having each six furnaces
3 ft. in diameter, or eighteen furnaces in all, with an aggregate fire grate
area of 300 square feet. The new boilers, fitted with the forced draught,
are likewise three in number, but single ended, 13 ft. in diameter by 11
ft. 2 in. in length, having each three furnaces 3 ft. 3 in. in diameter, or
nine furnaces in all, with an aggregate fire grate area of 112 square feet.
Air for combustion is supplied to the boilers by one of Messrs. W.H.
Allen & Co.'s fans, 5 ft. 6 in. in diameter, driven direct by an engine
having a cylinder 7 in. in diameter with stroke of 4 in. The boilers
removed had two stoke holds across the ship, one fore and one aft of
the boilers, while the new boilers have only one stoke hold on the after

side. The engines removed have cylinders 57 in. and 90 in. in diameter
by 48 in. stroke, while the new engines have three cylinders 31 in., 46
in., and 72 in. in diameter respectively, with piston stroke of 51 in.
During the trials the coals