longing 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 Messr