IM- PROVEMENTS IN THE PROPULSION OF TORPEDOES
Year: 1876

page_text: LETTERS PATENT to Farnham Maxwell-Lyte, of Paris, France, at present of
53, Chancery Lane, in the County of Middlesex, for the Invention of "IM-
PROVEMENTS IN THE PROPULSION OF TORPEDOES."
Sealed the 23rd September 1876, and dated the 24th April 1876.
PROVISIONAL SPECIFICATION left by the said Farnham Maxwell-Lyte at
the Office of the Commissioners of Patents on the 24th April 1876.
FARNHAM MAXWELL-LYTE, of Paris, France, at present of 53, Chancery Lane, in
the County of Middlesex. "IMPROVEMENTS IN THE PROPULSION OF TORPEDOES."
My Invention consists in the use, for the purpose of propelling torpedoes, as a
substitute for the compressed atmospheric air now employed, of one of the more
easily liquiable gases in the liquified compressed state, such as ammonia, sulphurous,
hydrosulphuric, or carbonic acids, or protoxide of nitrogen. Such liquified gases,
when at ordinary temperatures the pressure on their surface is sufficiently alle-
viated, boil and give off gaseous vapors possessing very high tensions. The
liquified gas which, however, is most specially adapted for the propulsion of
torpedoes, and which I specially desire to mention, is ammonia. Its vapor at
ordinary temperatures, say ten degrees centigrade, has a tension of about 6 atmos-
pheres. It is less liable than some others to freeze into snow by the cold of its own
evaporation; it is very soluble, and when disengaged under water no bubbles
rising to the surface need betray the silent progress of a torpedo moved by it. Its
vapor possesses great elastic force, and it is consequently eminently suited for
working expansively, while, by causing it to be absorbed by water, a vacuum may
be produced at each stroke behind the piston. It is cheaply producible by distil-
lation from solutions and salts of ammonia, and under these circumstances may be
made to condense itself under its own pressure into a clear mobile liquid in any
suitable refrigerator. It can be kept unaltered in iron vessels.
This special application of the more liquifiable gases and of ammonia in particular
in their liquified state for propelling torpedoes in preference to air or any other per-
manent gas simply compressed is for the purpose of causing the speed of the torpedo
to be maintained throughout its course with a constant velocity, and is the particular
aim of my Invention, since, so long as any liquid remains in the generator, so long
will fresh gas continue to be evolved, and the initial pressure on the working parts
of the motor will be maintained. On the other hand, with atmospheric air or other
[Price 4d.]

page_text: permanent gases compressed the tension rapidly decreases as the work proceeds,
and at the last moment when the speed of the torpedo should be greatest its velocity
becomes diminished and may have become exhausted, and it may frequently retain
insufficient power to burst through a net or any lines of defence, or even to explode
itself at all by contact.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Farnham Maxwell-Lyte in the Great Seal Patent Office on the 12th
October 1876.
FARNHAM MAXWELL-LYTE, of Paris, France, at present of 53, Chancery Lane, in
the County of Middlesex. IMPROVEMENTS IN THE PROPULSION OF TORPEDOES."
Hitherto the motive power for propelling torpedoes through the water has usually
been compressed atmospheric air applied to work a screw propeller, but one im-
portant disadvantage attending the use of compressed air is that it acts with a
gradually decreasing pressure during the course of the projectile, whose speed
becomes gradually diminished in consequence.
My Invention consists in the use for the purpose of propelling torpedoes (as a
substitute for the compressed air now eniployed) of one of the gases liquefiable
under pressure, which I employ in the liquefied compressed state; and the Invention
consists more particularly in the use of ammonia gas generated by a store of am-
monia anhydride in its liquefied form as the motive power. for working the engines
of torpedoes. The vapor given off by this liquid has a tension of about 6 atmo-
spheres at ordinary temperatures. It is less liable than some other liquifiable gases
to be frozen into snow by the cold of its own evaporation; it is also soluble in
water, so that when disengaged under water no bubbles will rise to the surface to.
betray the silent progress of the torpedo. It moreover possesses a very high specific
heat, and is thus eminently suited for working expansively, and its property of
being instantaneously absorbed and condensed by contact with water enables a
vacuum to be formed behind the piston of the engine at each return stroke.
This liquified ammonia anhydride is cheaply producible by distillation from
solutions or salts of ammonia, and under these circumstances may be made to
condense itself under its own pressure into a clear, volatile, mobile liquid in any
suitable refrigerator. It can be kept unaltered in iron vessels, and the gas is
without action either on iron, steel, or india-rubber, as well as on mineral oils and
several other lubricants.
The advantage of employing the more liquefiable gases, and ammonia gas in
particular, in their liquefied state for propelling torpedoes in lieu of air and other
permanent gases simply compressed is that the speed of the torpedo is maintained
throughout its whole course with a constant velocity, since so long as any liquid
remains in the generator so long will fresh gas continue to be evolved, and the
initial pressure in the generator will be almost uniformly maintained. On the
other hand, with atmospheric air or other permanent gas compressed, the tension
rapidly decreases as the work proceeds, and the speed of the torpedo consequently
diminishes, and at the end of its course, when the speed should be greatest, the
propelling power of the torpedo may be so far exhausted as to be insufficient to
burst through a net or other means of defence or even to explode itself at all by
impact.
The employment of liquefied ammonia gas for the propulsion of torpedoes presents
the further special advantages that the receiver or generator which contains the.
liquid may be surrounded by the condensing water, so that the temperature of this
water, raised by the condensation of the gas, is kept down by the evaporation of
the liquid in the generator. The torpedo may also be thus caused to maintain a
constant specific gravity throughout its course, there being no loss of the gas, which
becomes condensed entirely within the torpedo if so arranged.

page_text: Having described the nature of the said Invention and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
herein-before in part recited Letters Patent is the application and employment of
ammonia gas for the propulsion of torpedoes, as described, in lieu of compressed air
now used.
In witness whereof, I, the said Farnham Maxwell-Lyte, have hereunto set
my hand and seal, this Eleventh day of October, in the year of our Lord
One thousand eight hundred and seventy-six.
F. MAXWELL-LYTE. (L.S.)