Herald of the times. [volume] (Newport, R.I.) 1849-1856, 1853-05-05
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Boston, the city Of notions, they have
now on exhibition an atmospheric tele-
graph, which a correspondent Of The
Tribune thus explains for the benefit Of
those who are not engineers. Suppose
that cylindrical pump &c inches IN di-
ameter, with u AS inch stroke, be ccn-
nected with pipe IL iaches in diameter
and 36 feet long. The capacities Of the
pipe and the cylinder viii! be equal. If
the piston then lie raised from the bot
tom OF The cylinder 10 the top, The air
IN the plpe will have TO expand TO dNu-
ble lis space TO fill both the pipe and the
cy!inder, and while The pressure with
out ls d whole atmosphere, or Is lbs. 10
the square inch, the re action within is
only halt an aimosl here, or :! lbs. As
every upward stroke Of the piston is
sufficient 10 reduce ole hall the density
in SO Tee. Of pipe, by making 10 strokes
u minute and working 81 hours, it would
rarity TO the same exten, the air in 200
miles OF pipe. AT that degree OF ex-
! huustion, the external pressure Oh the
piston will be 1884 It's more than the
internal, and there will be a pressure OF
one ninth that, or 64S lbs, available TO
p.opel loud Though the pipe. As tie
pipe is nearly level, the resistance from
friction is nearly all that has t, be over
come by the propulsion. and conse-
quenily a mail OF 10000 IalEounGs let
,ers would be propelled by such II force
acting constantly, with enormous ve!o-
city. II would, in fact, he shot forward
hundred miles in very iew minutes,
and then, tie erial equilibrium beirg
restored, q resistance would commence
which would gradually destroy its mo
men,um. II, instead oi one pump, many
should be employed a, once in exhaust
ing the supposed 2oJ miles ol pipe, it IL
plain that the work nigh. be done in
single hour or less. One hundred horse
power OF steam, acting at different
points, would undoubtedly he able in an
hour TO produce u HropelIing force ap-
| y, oaching much nearer TO IA whole a.
mosphere, leaving, indeed, only air
enough in The pipe TO answer the impor-
tsnt Iurpcse Of re-acting spring or
GU hon "A, the remote end, SO as 10
prevent the mail from being shattered
or reduced to IL Homogeneous pup by
100 sudden arrival.
So Tar as The NAL itself is concerned,
1t will p'obabIy cost less tractive force
10 drag it bodily through "a pipe Of pret-
, ty smooth bore than 10 drag il with It's
proportion OF locomoti We apparatus
over railroad. The amount oil horse
power which would in a given tine
dag it from Boston TO New York,
would IN the same time exhaust pipe
Of sufficient bore to enable a,mos, hcric
pressure to put it through in Ten or FL
teen minutes. Multiply ing the horse
power applied TO the exhaustion wIl
reduce the time consumed in the same
proportion. And in this way we may
have hourly mails or half hourly, with
no greater expense TOR carrying them
than at present. As 10 the wear and
tear. that j. another matter. The tric-
ton on the bags might be little more
serious than at present, yet this dilficui-
~ may be reduced 10 triile. As the
load Is constantly in contact with cold
pipes. the heat from The friction will be
absorbed nearly as last as il is genera
ted, and there is lltue danger that the
mail will take fire. The apparatus, on
q small scale. which MIR. Richardson
shows at the Exchange, is very lngo-
niously constructed, and works PrettIy.
But OF course, no model so dimrnutive
can demonstrate the Feasibility OF tie
operation, in large. Neither does an
experimen, Of nile Of pipe, three inch
es in diameter, which was successfully
pu, in operation Oh the line Of the Prov
idence Railroad amount 10 a demon.
s,ration These experiments. however,
show the nature OF The force, how the
erial team is to he harnessed, and what
are its good points for the mail ser
vice.