, 1880-06-30

adopted in practice, but is that in which
the principle has been finally developed,
and is now being demonstrated. The air
is first compressed by o stationary engine
and machinery into the reservoir of the
air engine. In the present instance the
compression is effected by the machinery
in the Arsenal, by permission of the au.
thorities, who have also consented to Colo
mel Beaumont carrying out his experiments
there, seeing that the principle will find
an important application in several direc-
tons connected with the Government, nota-
bly, in that of electrically -steered t0rpedOes.
The air is stored in the reservoir under q
pressure of 1OO0lb. per square inch, and is
delivered thence into the first and smallest
cylinder at that pressure. After use there
it is expanded into the second n third
cylinders in succession, each cylinder hav-
ing an increased cubical capacity in rela.
ton to the one preceding it. From the
third cylinder, having there given out its
last pound of useful effect, the air is eject.
ed nOiselessly into the atmosphere from q
small port at the side of the cylinder.
The first cylinder being Of comparatively
small area, difficulty might he experienced
i'll starting the engine on q rising gradient
or in the presence of other re~siStances. To
meet this point there is an arrangement
for admitting the air at full pressure into
the second or intermediate cylinder, so
that greater power is thus developed at the
first stroke. Another difficulty invariably
present when highly. compressed air is OK.
banded is the extreme cold produced, which
as is we'll known, is so great that the
moisture in the atmosphere becomes con-
denSed and frozen upon the working parts,
thereby contributing to reduce the power
and efficiency of the machine, n in time to
ckox0 "a. ~ M I.AG~-1@x 80 ,,a% -
Colonel Beamont's engine by the applica-
ton Of heat, externally, to the compressed
air. This is effected by means of a diminu.
tive steam generator which is carried on
the framing of the engine. So effectual is
this application of a mild heat that the ex-
banded air issues from the exhaust ports
quite warm.
With this engine we lately made several
runs with very satisfactory results, the
machine working smoothly, noiselessly,
and at a good speed. A number of runs
were effected over a straight length of
that part of the Arsenal railway which
runs direct from the proof butts to the
Plumstead entrance of the Arsenal, the
length traversed being nearly 700 yards.
At starting the gauge showed a pressure
of 1000lb. per square inch in the air reser-
vOir, and at stopping this had become
lc.ltCCu W OAUlOs, lllAHo 0AOWtnE tAbO OAAAy
180lb. of pressure had been consumed in
the runs, which in the aggregate amounted
to a little over three miles. The engine
weighs 1O9 tons and a truck containing
several passengers which it hauled weighed
about ii ton more, making a total of IL
tons. The result of the runs, however,
was not considered SO good as had been
obtained upon previous occasions, as q
number of stops were made in order
to test the controlling and other qualities
of the engine. The engine is arranged SO
as to be able to make a run of 20 miles
with one charge of compressed air. What
it really has done, we are informed, has
been to haul a gross load of % Q for Q
distance of IL miles, and the lighter load
of IL tons for over 20 miles, with one
charge of air, and which it did under the
observation of the Arsenal authorities.
From these experiments it was deduced
that the engine will take three tons one
mile with the expenditure of one cubic
foot of compressed air. There can be no
doubt that the engine so far has worked
most satisfactorily, and there can be as
little doubt that the new pattern engine,
which we understand will SOON be running
on the Edinburgh and Portobello tramway,
will prove as successful. II cost of pro-
duction, maintenance, and working iS
found to be low, other things being equal,
there is a wide future before this system.
Not only will it be applicable for tramway
service, in which connection it has been
mainly developed by Colonel Beaumont
Init r. will nrohanlv ha found of