Evening star. [volume] (Washington, D.C.) 1854-1972, 1931-02-08

II has probably wondered If it would
ever be possible TO reach Luna.
- Writers of all ages have spun fanci-
full tales of trips to the moon. Even up to o
few years ago the sojourn was effected time
after time between the covers Of fiction books.
OF late, however, attaining Of terrific speeds
by rocket-propelled craft has caused trip TO
the moon to approach nearer to the realm OF
reality. People no longer smile when they hear
of some savant preparing to construct device
that will span the gap between earth and It's
nearest Eeighbor They have seen science en-
compass unbelievable things in the course OF q
few years. They might live to see space
ship screech upward to the moon They might
even have the opportunity of visiting the moon
themselves.
Those who expect to see travel to the moon
in this generation asking too much OF
science but in a little more than century
hence-in the year 1850, to be specihc-a rocket
craft from the earth will go roaring moonward
at the rate of 100 miles per minute.
The setting of the date 1850 for mans initial
flight to the moon was effected by John O. Stew
art associate professor of astronomical physics
at Princeton University, In a lecture before the
Brooklyn Institute of Arts and Sciences last
Spring. So wide and violent discussion
throughout the learned societies of the world
followed Prof Stewards announcement that he
was forced to clarity his position. This he did
at a recent lecture before the Amateur
Astronomers Association In the American
Museum OF NATURAL t11SCOIys NeW 4OAA' 1AC
not only reiterated his statement as to the year
1850 but he also advanced mathematical proofs
to back it up.
sIT Asst April in lecture before the Brook
~ lm Academy of Sciences, I made the
statement that If the present trend of increase
In vehicular speeds and powers continues the
moon actually will be reached about the year
1850 at a guess" says Prof. Stewart. This
very uncertain prediction has attracted wide
popular attention. should be sorry II IL were
accepted too confidently.
"As far as am aware, only four mechanical
means for travelling through nterplanetary
space have ever been suggested:
Inside q huge shell projected from a great
cannon, with speed in excess Of seven miles
per second
by utilization of the radiation pressure of
sunlight to oppose gravity.
''By employing some new influence which
would reverse gravitational action so that space
ship would be pushed away from the earth In
stead of attracted toward it.
Inside car propelled according to the prin-
ciple of a skyrocket."
OF these four methods, only the last deserves
the serious consideration of interplanetary
transportation engineers, says Prof. Stewart
1.-The merits of Jules Verne's description Of
the voyage by cannonban are chiefly literary"
he says. "A muzz!e velocity of about seven
miles second-or more, air resistance is
allowed for-1s requisite if a shell is to be shot
to the moon. Even If the barrel Of the moon
b0mbarding cannon were 100 miles In length,
the acceleration of the shell from the breech
TO the muzzle would require to be the order Of
the square Of the muzzle velocity divided by
twice the length Of the barrel, or 0neLquarter
mile per second, which Is 40 times the accele-
ration of gravity. Consequently, during the
half minute while the shell was travelling out
through the barrel Of the gun, the unfortunate
crew inside would be crushed by their own
weight which would be increased By factor
Of 40.