The evening telegraph. [volume] (Philadelphia [Pa.]) 1864-1918, 1869-08-25
SPIRIT OF THE PRESS.
II ditorInI Opinions Of the Leading Journals
Upon Current TOpics-COmphe" Livery
nav for the Evening Telegraph
vTEAMING AND ROWING-AN EN-
GTNEERING PARALLEL.
Fro,n the N. Y. Times.

Ai1--- GINEERING PARALLEL.
From the NJ Y. Times.
Ono of the most remarkable features of
modern steam navigation is the general sub
stitution of the screw for the paddle. In
deed the screw steamer has nearly driven lts
rivals from the stormy Atlantic, where the
merits of submerged propellers and heavy
spars are most manifest, and IS fast chasing
Them from more pacific waters the world over.
Tbe Persia. which but fourteen years ago was
considered the perfection of naval architect
,1re. was last year sold for Gl5,OOO to be
changed from paddle to screw. just as the
Cunorders were experimenting with their first
screws. the new French line to this country
was started with paddle ships. One of them,
tho WASHINGTON. which formerly steamed ten
niles an hour with 0G tons of coal per day,
has since been fitted with screws and now
steams 11'S miles with S3 tons of coal, and
The new ships of all Atlantic lines are invari-
ably propelled by screws.
The greater economy of the screw ship
with given speed and load, or her greater
sneed with the same fuel, are not due en-
J!relv to the fact that the efficiency of her
,1ronellers as compared with that Of paddle
wheels is less impaired by the rolling of the
Iessel-not entirely to the fact that the
screw steamer, by reason of the submerslon
of her propeller, and its independence OF the
rolling of the ship, can carry more canvas
and can sail on her beam ends as well as on
an even keel, as far as applying the engine
mower is concerned. Nor does the superiority
of the screw ship lie entirely in her greater
capacity for stowage, by reason Of the greater
compactness of her engines, nor yet III the
Improvement of her machinery for generating,
superheating, distributing, and condensln8
steam. since all these may apply equally to
the paddle steamer.
One of the notable differences between the
= IL 4
new practice and the old, both III ships ana
locomotives is the hjgh SpeH q ptS 10"
adopted in modern engines The paddle
engine is a great numbering, heavy machine,
moving at the moderate speed suited to the
paddle-wheel The screw engine Is compact,
LIGHT. and lively and it DulS the Qulrh Stt05c
demanded by the screw. A horse power Is
5000 pounds lifted one foot in minute, or
one pound lifted $4,000 feet in minute.
Now, the paddle-steamer punclple carried TO
excess would illustrate this law by IHgg5"g
170lUd the 81. 600 pound weight, and lifting
it q foot while the screw steamer would be
burdened only with the one pound, which 1t
would lift 5000 feet. The total power is
the same. but while in the one instance, a
LARGE percentage of it is neutralized in carry
ing itself-in carrying the cumbrous enginery
by which its great force works through
small space, in the other instance,
the enginery is small and light, because it has
only to transfer small 1Orce through great
space and speed does not weigh anything.
There are many illustrations of this law in
practice. The old style of locomotives with
immense driving wheels, big cylinders and
ponderous parts, has given place to light
moving parts small drivers, and quick stroke.
small cotton cord running at sixty miles
an hour through machine shop does the
work of cumbrous cranes crawling few feet
minute.
This engineering law and these illustra-
lions establish the correctness Of the quick
stroke adopted by the Harvard oarsmen as
compared with the long, slow, beam-engne
stroke of their opponents. Speed is an ele
ment of power that weighs nothing. If some
element that is ponderous is substituted fol
it, part of the total power is lost in the
machine itself
The HeraJd, in late article on the inter
national race, prOpOunds a mechanical theor,
of the quick stroke which we commend t.
the consideration of learned bodies. Say
the Herdyd;-
''The oftener the oar falls into the water with
pull the faster wiz the boat be propelled 1t is o
TINS principle that the blades OF the steamboat Whee
have been multiplied, and placed six inches apar
instead OF three feet as formerly
Although this illustration does not apply t
the case in hand, it is very correct excer
that, as q matter of fact and practice. tn
floats of steamboat wheels are placed four t
six feet apart instead of six inches, becaus,
if placed at six inches the slip would be e,
cessive-the wheel would roll in the watt
like a barrel without taking hold, and IL
vessel would hardly move at all. We hoI
the Harvards' practice will not illustrate Ii
UelaLd'S theory.