Meigs County telegraph. [volume] (Pomeroy [Ohio]) 1848-1859, 1853-05-31
The Atmospheric telegraph.

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In Boston, The city os notions, they have
now on exhibition an atmospheric telegraph,
which a correspondent Of The Tribune thus
explains for the benefit Of those who ara
moi engineers: Suppose that cylindrical
pump So inches in diameter. with q AZ inch
stroke, be connected with pipe IL inches
in diameter and SO feel long The capaci'
lies of The Pipe and cylinder will be equal
If tho piston then be raised from the bottom
Of The cylinder TO the top. the air in The
pipe will have 10 expand to double lis space
to fill both The pipe and the cylinder, and
while The pressure without is whole Amos
phete, or is pounds 10 the square inch, the
re-ac,on wi,hin,s only hal aniaimosphere.
or u pounds. As every upward stroke Of
The piston is sufficient TO reduce one|half
the density in SO lee. Of pipe by making l6
strokes q minute, and working 80 hours. il
would rariIy 10 The same exlen. the air in
200 miles Of pipe. AT that degree oil ex.
haus,ion the external pressure on The piston
will be 1884 pounds more than The inlernal,
and there will be pressure of one.ninlh
that, or 848 pounds available 10 prope a
load through The pipe. As The pipe is nearly
level, the resistance from friction is nearly
all that. has 10 be overcome by the propul.
sion. and consequently mai of 10000
half.ounce letters would be propelled by
such force acting constantly, with enormous
velocity. 1t would, in facI. be shot forward
hundred miles in very few minutes, and
then the aerial equilibrium being restored, a
resistance would commence which would
gradually destroy It's momentum. II, instead
of one pump, many should be employed at
once in exhausIng The supposed 2oo miles
of pipe, il is plain that The work might be
done in single hour or less One hundred
horse power Of steam, acting nj different
points, would undoubtedly be able in an
hour to produce a propelIing force much
nearer to q whole atmosphere, leaving, in
deed, only air enough in the pipe 10 answer
The important purpose of re'aciing spring
OF cushion al The remote end, SO as 10 pre-.
ven. the mail from being shattered or re-
duced 10 homogeneous pulp by 100 sud-
den ar.vals ~ -G.
So far as the mail itself is concerned. it
will probably cose less tacyve force to drug
il bodily through a pipe of preuy smooth
bore Than 10 drag iI'w'h its proportion of
locomotive apparatus over railroad. The
amount Of horsepower which would in a
given lime drag it from Boston TO New York,
would in the same time exhaust a pipe Of
sufficcn, bore TO enable atmospheric press.
ure 10 put il through in ten or fifteen min.
u'es. Multiplying The horsepower applied
10 the exhaustion will reduce The time con.
sumeG in The same proportion. And in this
way we may have hourly mails, or half
hourly, with no greater expense for carry.
ing lhem than Al present. AS 10 The wear
and tear, that is another matter. The fric.
ZION on the bags might be little more se'
rious than at present, yet this difficulty may
be reduced TO uiAe. As the load is con.
4 sIanIly in contact with cold pipes, the heat
from the friction will be absorbed nearly as
fast as it is generated. and there is liule
danger ihut the mail will take fire. The
app raus, on q small scale. which Mr.. Ri
chardson shows at the Exchange, is very
ingcniously constructed, and works prct,iy.
Bur, Of course, no model so diminutivo can
demonstrate the feasibility Of the operation,
in large. Neither does an experiment, Of q
mile Of pipe, three inches in diameter
which was successfully put in operation On
| the line of the Providence Railroad. amount
10 demonstration. These experiments,
however, show The nature Of the force, how
The uerial team is 10 be harnessed, and whal
are lis good points for The mail service.