Courier Democrat. (Langdon, N.D.) 1891-1920, 1891-09-03
SCIENCE AND ]. PROGRESS.
,.rEREsTlNGs MATTERS FOR IN
: CURING MINDS.
N.w dynamite Gun--The Practl-
cal Man and the SCIENTIST
Manufacture Of Watch
Glasses--The Won
ders ofthe CAM
era.
A New Dynamite Gun.

:" .
While DR.. Joel G. Justin ofSyracuse
!. still bent on using shells charged
With dynamite in powder guns, and
while Mr.. Louis Gathman OF Chicago
= engaged on the same problem, Lieut..
James w. Graydon, formerly OF the
United States navy and now president
Of London, is devoting himself to the
system OF propelling enormous charges
Of the high explosives with a gun in
which compressed air is the motor.
The weapon is supported at the
hreech end on fixed trunnions fifteen
inches in diameter, which are bored
for the passage Of the compressed air.
howard the muzzle it is carried on
movable trunnions engaged with two
forged steel arms or levers. These
levers have sliding fulcra and are
actuated by hydraulic plunger for
the purpose of elevating or depressing
the gun. The breech is closed by
means of a steel screw block with in
terrupted threads, as in heavy
ordnance. A peculiar feature OF this
gun is that it can be loaded at any
degree of elevation within it's working
range, and it's rate OF discharge is
stated to be one round minute.
Pivoted to the breech trunnions
there is a loading slide or tray for
the reception Of the projectile. This
slide, at all times when the barrel is
elevated above the horizontal line,
rises by hydraulic pressure to receive
the projectile from a tram trolley. By
opening a valve the slide is then made
to descend with it's load, and is
brought into line with the barrel OF
the gun. On each side of the barrel is
fixed a small doube-acting hydraulic
cylinder, the plungers of which not on
" control the movement OF the load
ing slide, but also by their continued
action draw the projectile up into the
barrel, where it is held. The breech-
closing block, suspended above the
trunnions by CONFERENCE.-The, then de-
sends, and is also drawn into the
breech by the crosshead OF the n.y.
draulic plungers and locked.
1t has thirty-two compressed reser-
voirs, carried in four sections Of eight
each, two on each side OF the gun car
rage. These reservoirs are each ten
inches in diameter and four feet high,
and are tested to q pressure OF four
tons IL square inch.
Filled with air compressed to 5000
pounds square inch, or about l.
34Oth of it's original volume, the ca
pacity OF each at the working pressure
is about 1900 cubic feet OF air,
weighing HOO pounds i'll it's COM
pressed condition. Any number out
OF the four sections may be discharged,
according to the range desired OF the
weight OF the projectile. The discharg-
ing valves are a peculiar arrangement
OF the piston type, and are packed on
the hydraulic system. The carriage
on which the barrel is mountedis con-
structed of steel plates, with trunnion
bearings of cast iron, secured to it by
means OF turned bolts.
The Practical Man and the Scien-
list.
For the sake OF illustrating the diff
ference between the practical man and
theorist, let us suppose two persons
to visit the northern peninsula Of
Michigan seeking for iron. The one
runs along blindly, takes up with
every good show. and mines. The re-
suit is, he either makes a happy strike
by mere accident, or spends thous-
ands of dollars in useless search: The
other has studied the laws OF electric
ity, and knows that certain ores Of
iron are magnetic. He understands
also that these ores will exert theirin-
t1uence through any amount of super
incumbent earth. Consequently he
provides himself with dipping-needle
and compass, and by the operation of
these tells where bed is located, it's
approximate depth, and probable
amount OF material. To prevent be-
ing deceived by the magnetic schists in
that region, by means of his dipping
needle and compass he traces up the
bed until he finds an outcrop. Thus
have been located, at little expense,
many OF the mining regions of that
locality. What an achievement is
this, and how much better than the
blind guesses of the so-called practical
man!-Science Monthly.
Manufacture of Watch Glasses.
In the manufacture of watch glasses
the workman gathers with the blow
ing tube several kilograms of glass.
softening this by holding it to the
door of the furnace, he puts the end