The Helena independent. [volume] (Helena, Mont.) 1875-1943, 1892-04-22
RACE ACROSS the OCEAN
Development Of Speed and Eff
cheney in Vessels That Ply
the Atlantic.
Decrease in the Amount of Coal
Required for a Given
=Egz HORSEPOWER.
Increase of Boiler Pressure Present
shape OF Steam Vessels Not Likely
to Be Altered.


In a recent number Of the Scottish Re- |
view. Prof. Henry Dyer gave an interesting !
article on the race &C 7oss the Atlantic. in !
which, says the Industries, he traces the
development Of steamships and their ma
chinery, and gives figures to show the in
crease in speed and efficiency. After a pre-
liminary notice of some of the earlier at
tempts at steam navigation, Prof. Dyer
devetes = little space to clearing the repu-
tation of DR.. Latdner of some of the
charges which are sometimegbrouRht against
him in connection with ocean naviga-
tion by steamships, and he expresses the
opinion that, while d. Lardner may have
erred in the way of over.caution, and have
failed to estimate the possibilities both of
engines and ships, as be based his ~calcula-
tions on q coal consumption of twelve
pounds per indicated horse power Per hour.
with a speed Of eight knots, he doss not de-
serve to be held up to r%idicule, as he gen
orally ia when his name is mentioned in
connection with the early attempts at trans
atlantic navigation.
The development of the marine engine
forms an interesting study. both from a
theoretical and a practical point of view,
AAO AC0ta VI Al iuSloas6 VI Lae pressure
OF the steam. the action of the steam jacket
and of multiple cylinders. and the present
position of practice are all traced by Prof.
Dyer, and they, combined, show the great
improvements which hava taken place.
Those are roughly Indicated by thu amount
of coal consumed per Indicated horpe
power per hour. Until about 1880
the boiler pressure seldom exceeded thee
pounds ON the aqusre inch above that of the
atmosphere. From that date a grand in
crease took place, and in 1916 the average
was about ten pounds per square inch. By
1850 it had reached fifteen pounds. In 1sse
Randolph. Elder d Co. employed pressureao Of
thirty pounds in their compound engines,
but it WAS not till almost ten years later
that such pressures became general in tho
merchant service. On the compound en-
CINE common. pressures suddenly
rose to sixty pounds. and III some cases to
eighty pounds and 100 pounds per square
inch. and now for triple-expension nglnes
the average is over $50 pounds, while for
quadruple expansion engines it is 200
pounds per square inch. With regard to
seal consumption, the earliest marine en-
Rines must have used very nearly ten
pounds per Indicated horss power per
hour. In tho vol known side lever engines
it was about seven pounds. while fer en-
gines in use before the general introduo.
ton of the compound typo four pounds t,
four and a half pounds was the average
Randolph, Elder 81 Co., with their com
pound engines, had an average of from
two and a half pounds to three pounds
In 1877, when the compound sngin
had been in use for som
years. tbs average was found to be 81
pounds, being = saving of nearly 50 per cen
over the ordinary engines. while in 1873
there was a reduction to 1.828 pounds, or
further saving of 1887 per cent. Wit,
srlpls q QuAdrupls expansion snglnel