New-York daily tribune. [volume] (New-York [N.Y.]) 1842-1866, 1855-08-14

A recent srticle Of ours on Locomotion, not
protesting to be very scientific, has proyokedthe
criticism Of Tie Scientific Ameriean. We said that
but for the resistance of the air. with the engi-
neering requisite for the circumstances, speed
Of hundreds Of miles an hour might be attained
on railroad eeOnomieauy-we did not say how
safely. The Scientific american thinks the at
mospheric resistance to locomotive trains quite
trihing and treats ii as no obstacle st all to the
increase of speed. Not content with assertion,
it proceeds to " demonstrate" Assuming that
the atmospheric resistance at velocity OF 90
miles an hour is equal to l2t ft per square foot,
and that the only surface on which ii acts to re-
tard the train is the front Of one of the cars say
so square feet, it makes the whole resistance
from this cause 625 ft, while it attributes to the
moving power force Of more than $1,000 Is.
This denomination may be very good as far as
il goes but it does not 90 quite the length of
the subject.
Admitting tie train to be reduced to single
car, and thus to present only 90 squaIe feet IN
stead of 500 or loco, as actual trains often do
to the resistance of the air, it still remsins true
that the resistance will increase in the duplicate
ratio of the velocity, and when the velocity be-
comes enormous it will perhaps increase even
faster. Hence at 200 miles an hour it will be
10 900 Is, and at 400 it will be at least 40, 900
ID. Therefore, if We could abolish friction en-
trely, these high speeds could not be econom-
ically attained against the resistance OF the air.
without that resistance, provided any means
could be found of avoiding the heat generated
by the friction ofwbeels, and their flying of the
track. the friction ITSELF which is independent
of the velocity, We suppose might be more
cheaply overcome at high velocity than low
one, for it would be no greater while it lasted,
and il would not last so long. We often see a
man who has heavy load to carry given
distance run with it instead of walk, as an
econ )my of strength. A locomotive might save
in the same way, if it did not lose by increased
resistance. This was all the meaning we in-
tended to convey by our remark which The Sci
entife american prOnounces erroneous.
To determine the speed of railroad carriages
there are evidently other things to be considered
beside weight, friction, velocity, and atmos-
pheric pressure, which it is not our province or
purpose to discuss. But when you have got rid
of atmospheric resistance it is obvious that sny
constant force which is more than able to move
a load will on level cause it TO move with an
accelerated velocity, like that of falling body.
Whether, therefore, it is practicable to increase
the speed of railroad trains or not, we see no
impracticability in Mr.. Richardson's plan OF i'm
parting high yelOcties to loads properly en-
yeloped, in unctuous tubes, where flying OIL the
track is impossible, and heat cannot be accumu-
lated because tco surfaces are not rubbed TO-
gether for any length of time. The Scientific
american says we have exaggerated the ad-
yantages of this plan of locomotiOn into the re-
gion of fable. Wilt please to show what is the
precise limit of these advantages in the region
of fact If it be true that the resistance of
the air is not what has limited railroad speed, it
does not follow that loads cannot be sent 200
miles an hour in a tube by atmospheric pressure.
If the laws of nature forbid that they should be,
why will not our scientific critic show it 1t is
one of the Offices of science to disabuse the pub
lie and expose follaces which might mislead the
enterprisino and over. sauQuine