The weekly herald. [volume] (Cleveland, Tenn.) 1876-1888, 1877-04-19
SCIENTIFIC.

A Neio Compressed Air RdilUaV.-
Some interesting experiments have
lately been made in Geneva, SWitzer-
land, on a new system of cOmpulsiOn
by compressed air, the invention of NJ.
CONN. The road upon which the in
yeDtiOn is TO be practically employed
connects Ouchy, on Lake Geneva, with
Lausanne, the line following a grade
of 12 in $50. For two thirds of the dis
lance, which is but 1850 feet, traction
is accomplished by metallic cables
driven by hydraulic motors; over the
remaining third, the vehicles are moved
by a piston travelling in a long air tube
and impelled by compressed AR.
In the recent experiments a section
of the tube,l2S feet in length was used.
The interior diameter was 9'75 inches
and the thickness 0'46 inch. The total
weight was $50 lbs. On the upper side
a slit was made, with its edges flaring
inwards, in which an angular valve
fitted. The lateral faces of the valve
were covered with leather; and 1t was
was pressed against its seat by cOiled
springs fastened on the outside of the
tube. The piston inside the tube was
composed of six cast iron disks, with
leather washers between them, the
latter being cut a little large so as to
pack the tube tightly. The piston
rod supported three rollers, which
served as guides to keep the piston in
the axis of the tube. Between rollers
and piston, the propelling bar was at
tached. This was made of such a form
as, when the valve in the slit above
was lowered, to extend up between
said valve and one edge of the slit. Its
upper end then came IN contact with
the vehicle; and thus the motion Of the
piston was transmitted TO the latter.
In order to cause the lowering of the
valve lust in advance of the bar, the
car carried a roller which pressed upon
a band of metal which rested on the
valve rods, the latter being extended
up through the springs.
A small COMPRISING engine supplied
air to a reservoir, whence it was drawn
at a pressure of about 10 atmOspheres.
The objects of the experiments was
principally to determine the staunch-
ness of the valve, and IN this respect,
the Revue Undesirable states, they were
entirely successful.
DO not Face the Light When at Work.
Statistics kept by Oculists employed
in intirmaries for eye diseases have
shown that the habit of some persons
in facing a window from which the
light falls directly in the eye as well as
on the work, iDjure their eyes in the
end. The best way is to work with a
side light, or, if the work needs strong
illumination, so that it is necessary to
have the working table before the
window, the lower portion of the latter
should be covered with a screen, so as
to have a top light alone, which does
not shine in the eyes while the head is
slightly bent over and downward to-
ward the work.
In the schools in Germany this mat
ter has already been attended to and
the rule adopted is to have all the seats
and tables so arranged that the pupil
never faces the windows, but only has
the side lights from the left; and as a
light simultaneously thrown from two
sides gives an inference of shadows, it
has been strictly forbidden to build
school rooms with windows on both
sides, such illumination having also
proved injurious to the eyes of the pu-
pills.
We may add to this advice not to
place the lamp in front of you when at
work in the evening, but a little on one
side; and never to neglect the use of a
shade so as to prevent the strong light
shining in the eyes. This is especially
to be considered at the present time,
with kerosene lamps, with intensely
luminous flames, becoming more and
more Medical Journal.