The Washington weekly post., 1899-05-09
CTHE E,,DD
USES FOR LIQUID AIR.
Engineers Considering the Possibilities oil
the New Power.

the New Power.
From the Engineering Magazine.
1t would seem that certain uses may De
found for liquid air in which considera-
tions of cost are not so important as Is the
ability to obtain the effects in view. In
warfare, for example. the possession OF
highly concentrated energy-stores under
control is very important. Liquid air can
be rapidly converted into compressed air
at six tons per square inch. This would
probably be useful in the projection cf
high explosives. Compressed air is now
used for propelling mobile torpedoes' or
fsh-tcrpedoes, as they are called DlTlgi-
BE torpedoes either depend for power
upon compressed air or the electric energy
of a storage-batteTy. Compressed AIR re-
auires high pressures and very strong and
heavy containing vessels. Liquid Iii can
be stored without pressure or at low
pressures and can be evaporated ;tt any
desired pressure, while its bulk represents
that of air under $40 atmOSpheTeS. "A
stCrage-h battery would probably be from
five to ten times as heavy as hquelled ar
| in a receptacle, for equal available energy.
But 10 storage-battery could be discharged
at an equivalent rate.
Submarine boats and flying machines
NAV vet find use for liquid air. In Inc
! submarine boat it could be evaporated py
the heat of the surrounding water, ana al
ter furnishing power it would ventllate the
boat Before the final discharge 1t could
he burned with oil in a fuel engine for
| further power. We may lind use Tor IL III
the flving machine For emergency work
II could In evapCrating cool the cylinders
of a fuel-engine and yield power as re-
Z O.
ence of a boat could be effected by the
use of liduid air, so easily gasified, 10 add
! TO the displacement.
| The great feature of the application or
| such a pcwer as liquid air would be its
| emergency value, BY this is meant the
! ability TO obtain at will sudden output
| far beyond the normal. Animal power
| notably possesses this emergency value,
and the success of electric trolley systems
| largely depends upon the fact that, When
needed, the station can be called upon
| for a temporary delivery to any single
car or train, of a power greatly IN excess
! OF the rated output OF the motors.
| A fascinating speculation for the cleo
| trical engineer is the possibility OF so
cooling the conductors of electric lines or
apparatus as to improve the cOnductlVlty
many times. and 50 diminish the losses
| in any given length of conductor, ana at
the same time greatly improve the in
| sulation. Profs. Dewar and Fleming nave
/ shown, however, that 1t Is condltlOn OF
| this enormous Improvement in conductiv-
! ity that the metals be pure, very small
| percentage OF impurity greatly lessenlng
| the result. AS regards the insulation.
! they have shown that dielectrics and even
| electrolytes become inSulatOrs OF excel
| lent character when cooled TO the temper
ature of liquid air What effect such a
/ lowering of temperature would have upon
| the dielectric strength or striking dis
| tanee between conductors at great differ
| ences of potential is not as yet determin-
I ed, so far as the writer iS aware The
| result to be expected from a consideration
| of the effect of heating upon dielectrie
| strength or striking distance is that very
| low temperature Will make ii far more
| difficult to break down insulation by
| sparkling through it,
| That the electrical engineer cOVetS Just
| such agencies as will thus extend the
| range OF possibilities in his art needs no
proof He would be apt 10 choose a pipe
line conveying liquid air as the very best
| loca ton for his conductors, assumed to
| be made of as pure metal as pos slble, the
high insulation probably attainAb!e being
! the chief object. Whether his conductors
| were placed outside such a pipe line or
! within the same, he could no doubt adapt
| himself 10 the conditions, provided he
| could get the benefit of the low Ienpera-
| ture insulation, and possibly, TO GER
tain extent, gain in conduction-