Walker Lake bulletin. (Hawthorne, Nev.) 1883-1926, 1895-10-02

are no less than four hundred applica-
tions ON file at the Patent Office at
Washington for patents for pneumatic
tubes.
In 1892 the United States Govern
ment contracted with a pneumatic
transit company for the laying of two
tubes from the General Postoffice, cor
ner of Ninth and Chestnut streets,
Philadelphia, connecting with the sub
postoffice on Chestnut street. above
Third, which is over half a mile away.
Wrought iron and brass tubes were
tried but gave no successful result.
Only one resource remained and that
was to take cast iron pipes and bore
them out. Twelve special machines
were constructed and the process of
boring commenced: less than three
months later the tubes were ready to
be laid, but not before almost every
iron firm in the country had been re-
quested to perform the work. The abb
solu6e necessity of an even bore was a
problem that proved too much for the
manufacturers.
On February II. 1898, Postmaster
General Wanamaker sent through the
tubes the first carrier containing
Bible wrapped in the American flag.
Since that time the tubes have been in
continual use for transmitting mail
The success of this venture warranted
the company perfecting a system which
for magnitude and practical benefits
will have no equal anywhere. At
present the distance covered is 2,928
feet. and as there are two tubes. one
leading tube and one returning, the
total length of the tubes is 1856 feet.
The tubes are 1-8 inches in diameter.
The pipes are laid about four feet
under the surface of the street, but in
order to escape the network of pipes
and conduits encountered at street
crossings it was necessary in places to
reach depth of thirteen feet, and the
pipe follows grades as high as six feet
in hundred. In the basement of the
main postoffice is located the duplex
air compressor with steam cylinders
bored ten inches in diameter and air
Cylinders of eighteen inches bore.
A continuous current of air flows
down one tube and returns through
the other, thus making practically one
long tube in the form Of loop, with
both ends at the main postoffice, and
means of exit and entrance at the SUBJ
postoffice without the escape of air.
The carriers are made of steel, with
fibrous rings to bear against the inte-
rior of the tube. A hinged lid closes
and locks the carrier before insertion
in the tube, and once in the tube the
carrier cannot become unlocked. The
carrier is about Is inches long and 5 "a
inches in diameter. and holds from 100
to 200 ordinary letters; 10 of them can
be dispatched in minute, making
delivery of /, 800 letters per minute or
30. 900 per hour each way. grand
total of 1870, 900 letters per hour. This
is capacity far beyond the require
ments of the postal service, and shows
the enormous extent to which the sys-
tenn of pneumatic tubes can be applied.
The plant for carrying the mail from
OlO POouOIuOO w UhO OUhOl was pun
down free of cost to the United States
Government So successful was the
system that at the expiration of the
time the Government made arrange
ments for its continuance.
Last month the company secured an
ordinance, which has been approved
by the Mayor, to lay two tubes of
f1ve.eighths of an inch in thickness.
one eight inches and one three inches
in diameter. These will be laid in the
same trench, the former to carry all
mail packages and merchandise of the
average size of dry-goods package,
the three-inch tube will be used ex-
clusively for dispatches.
There is an average of $4,000 mes
sages sent through the pneumatic tubes
in London every day. 1t requires
about eleven minutes to send the aver
age telegraphic dispatch, both in Eng
land and this country, from point to
point, exclusive of the time for deliv-
cry. The Philadelphia company will
send any dispatch to a point in the
most remote part of the city in an
equal time.
The company will lay the pipes near
the large business centres, dry goods
stores. banks. financial institutions and
most densely populated parts of the
city. Sub-stations will be located at
not more than quarter of a mile
apart. which would leave about two
hundred yards to be travelled by the
boys in delivering messages for pack
ages.
The projected length of line for the
new tubes is about fifty miles, with
no less than two hundred sub. stations.
In the vicinity of Twelfth and Market
streets central pumping station will
be established, containing air COM
pressors. boilers, tanks. etc. This will
be used not only as pumping sta
ton, but a central station or exchange.
From this central station double line
of tubes will be laid in as direct
manner as possible to fifteenth street
and Columbia avenue, where another