IMPROVEMENTS IN THE APPLICATION OF CARRONIC ACID GAS TO MOTIVE PURPOSES
Year: 1852

page_text: LETTERS PATENT to Thomas Allan, of Adam Street, in the City of
Westminster, Civil Engineer, for the Invention of "IMPROVEMENTS
IN THE APPLICATION OF CARRONIC ACID GAS TO MOTIVE PURPOSES."
Sealed the 16th March 1853, and dated the 1st October 1852.
PROVISIONAL SPECIFICATION left by the said Thomas Allan at
the Office of the Commissioners of Patents, with his Petition, on
the 1st October 1852.
I, THOMAS ALLAN, of Adam Street, in the City of Westminster, Civil
Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE APPLICATION OF CARBONIC ACID GAS TO MOTIVE
PURPOSES" to be as follows:-
The ratio of increase in volume and consequent pressure on the
square inch being so rapidly and dangerously affected by the slightest
increase of temperature has hitherto rendered this vapour quite un-
controllable, and consequently unavailable when applied to an engine or
other similar machine.
I propose to take advantage of this immensely elastic force for pro-
pelling vessels, and to apply it under and against the water at high

page_text: degrees of pressure. In this mode of applying this elastic power its
explosive nature would be turned to good account, and would be
rendered safe, there being no reservoir of danger as when used in the
same manner as steam to work an engine. The rapidly formed elastic
force of this gas on the water, a non-elastic fluid, would produce a
powerful impulsive effect.
The acid and alkali forming the gas would require to be pumped into
the closed end of a long tube or chamber, the other extremity being
open and debouching under the-water, and heat being applied at an
intermediate portion of the same would cause a rapid expansion or
rather explosion of the gas. A tube or chamber of the horse-shoe form
might be most suitable, the vapour generated at the bend and issuing
from the two ends debouching under the quarters of the vessel.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Allan in the Great Seal Patent Office,
on the 1st April 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
THOMAS ALLAN, of Adam Street, in the City of Westminster, Civil
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of October, in the year of
our Lord One thousand cight hundred and fifty-two, in the sixteenth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Thomas Allan, Her special licence that I, the
said Thomas Allan, my executors, administrators, and assigns, or such
others as I, the said Thomas Allan, my executors, administrators, and
assigns, should at any time agree with, and no others, from time to time
and at all times thereafter during the term therein expressed, should
and lawfully might make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle
of Man, an Invention for "IMPROVEMENTS IN THE APPLICATION OF CAR-
BONIC ACID GAS TO MOTIVE PURPOSES," upon the condition (amongst
others) that I; the said Thomas Allan, by an instrument in writing

page_text: under my hand and seal, should particularly describe and ascertain the
nature of the said 'Invention, and in what manner the same was to be
performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that I, the said Thomas Allan, do hereby declare
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by
the following statement, that is to say:
My Invention consists of a mode of employing carbonic acid gas for
the propulsion of vessels by heating the same to any desirable extent,
and taking advantage of the expansive force resulting from the increase
in volume of the gas due to such heating. The rapid rate of increase
in volume undergone by carbonic acid gas on the application of any
considerable heat or increase of temperature has hitherto rendered
that agent almost uncontrollable, and consequently unavailable for
motive purposes when employed to actuate machinery on principles
analogous to those of the steam engine; but according to my method
of employing the gas this property is turned to a good account, and
the immensely elastic force, which would be destructive of almost any
arrangement of machine which it might be used to actuate, will, when
the
gas is rendered an impellor and directly applied against the water
on a similar principle to what has been essayed with jets of water or
heated air issuing at high velocities, enable the propulsion of vessels to
be safely and economically effected, and high rates of speed attained.
The mode in which I have found it convenient to carry my improve-
ments into effect is as follows:-I cause the gas to be generated at the
inner extremity of a long tube or chamber fixed in the interior of a
vessel, and whose outer extremity (or extremities where the tube or
chamber is formed with branches) is open to the water at a point
below the water line of the vessel. The inner extremity of the tube or
chamber is closed, but provided with a valve or valves opening inwards,
through which the materials for generating the gas are supplied.
These may consist of dilute muriatic or sulphuric acid, and a suitable
alkali, or chalk, or marble, or indeed any materials capable of evolving

page_text: carbonic acid gas. At a point intermediate of the extremities of the
tube or chamber I apply a furnace, the heat from which playing
around the exterior causes the expansion, or it might almost be said
explosion, of the gas in the tube, which debouching against the exterior
water effects the propulsion of the vessel.
And having now described the nature of the said Invention, and
in what manner the same is to be performed, I declare that what I
claim is,-
The mode of employing carbonic acid gas, when expanded by an
increase of temperature, for the purpose of propelling vessels by impul-
sion, in the manner hercin-before explained.
In witness whereof, I, the said Thomas Allan, have hereunto set
my hand and seal, this Thirtieth day of March, One thousand
eight hundred and fifty-three.
THOMAS ALLAN. (L.S.)