IM- PROVEMENTS IN PROPELLING
Year: 1854

page_text: LETTERS PATENT to Charles Augustus Holm, of 21, Cecil Street, Strand,
in the County of Middlesex, Civil Engineer, for the Invention of "IM-
PROVEMENTS IN PROPELLING."
ealed the 28th April 1854, and dated the 14th February 1854.
PROVISIONAL SPECIFICATION left by the said Charles Augustus Holm
at the Office of the Commissioners of Patents, with his Petition, on the
14th February 1854
I, CHARLES AUGUSTUS HOLM, of 21, Cecil Street, Strand, in the County of
Middlesex, Civil Engineer; do hereby declare the nature of the Invention for
"IMPROVEMENTS IN PROPELLING " to be as follows:-
When the present mode of propelling vessels depends on obtaining the
propelling action, or "point d'appuis", in or by means of the medium in which
the vessel floats, or as in the case of a railway locomotive, by means of
the weight or pressure of the wheels on the rails or ground, my Invention is
such, that by the percussion of a fluid on curved plates, or by the percussion
of a fluid on curved flanges on a revolving disc, or by the unbalanced atmo-
spheric pressure. produced by the movement of a fluid within proper channels
of a revolving disc, I am enabled to obtain a greater propelling traction than
by any other means, for the purpose of propelling carriages and vessels.or

page_text: other floating bodies, entirely independent of the rail, ground, or medium in
which such bodies move or float..
Now, in order to obtain the propelling percussion on the curved plates, I
elevate a liquid, by means of my patent centrifugal screw pump, to any required
height within a suitable chamber, and if such heights be considerable, I submit
the liquid to a pressure by means of allowing the air within such chambers to
be compressed, and by means of suitable constructed passages and valves, I
allow the liquid to be discharged on a series of curved plates, such plates being
portions of a cylinder of about a quarter of a circle, when the percussion of the
fluid on such curved plates produces the propelling traction; the liquid escaping
from the curved plates is immediately received and elevated by the centrifugal
screw pump, and thus a continuous motion of the same quantity of liquid is
produced; the curved plates and the pump are enclosed within a suitable
casing, which is fastened to the body to be propelled; when it is required to
produce a backward as well as a forward propelling action, a double series
of curved plates is necessary, and the screw pump will then be placed between
the two series; the motive power is applied to work the shaft of the screw
pump, and by the closing or opening, for admitting fluid to the backing or
propelling series, a backward or forward propelling action is produced.
This propelling apparatus may be arranged under an infinite variety of
forms, according to the propelling power required or the nature of the body
to be propelled; thus, for instance, instead of having the curved percussion
plates of a quarter of a cylinder, an apparatus may be produced with percussion
plates composed of one half of a cylinder; and when the apparatus is worked
under a great pressure it will be necessary to break or diminish the length of
the jet when it leaves the half cylinder, in order to prevent the jet from striking
the casing or other parts, by which the propelling action would be lost; and to
thus diminish the length or velocity I allow it to strike against a series of
angular plates, so arranged that none of the propelling power shall be lost, and
the velocity of the jet considerably reduced before it enters the centrifugal screw
pump; and further, as another expedient of increasing the propelling traction
and diminishing the final velocity of the jet, I first allow the current to strike
against a large percussion plate of half a cylinder; I then allow the jet when
it leaves this cylinder to strike against another half cylinder of much smaller
diameter, by which the direction of the current becomes reversed; and when
the current has passed this half cylinder, it further strikes against another half
cylinder, of larger diameter than the first, and thus by the combination of large
and small semi-cylinders, the propelling percussion will be increased at the same
time: as the velocity of the current when discharged becomes reduced; the

page_text: percussion on or within the large semi-cylinders being positive, and the per-
cussion within the small cylinders negative, and the effective percussion for
propelling will only be equal to the difference of percussion produced between
the larger and smaller semi-cylinders.
I have now described a propelling apparatus composed of curved plates and
a centrifugal screw pump, and will now describe another modification, which
consists in the combination of these two parts, namely, the centrifugal screw
pump and the curved percussion plates into one, when it assumes the form of
a disc; the central passage of the pump is then open on both sides, and pro-
vided with a right and left handed screw, in an opposite direction and of equal
diameter to the central orifice. Now, if at the circumference of the pump a
curved flange, having a curve equal to one quarter of a circle, the current
would then leave the disc in the form of a hollow cylinder and a propelling
percussion produced on the curved flange, it will then be necessary to change
the cylindrical form of the current into that of a disc, because if it were
allowed to continue in the cylindrical form, it would strike against the casing
in which the disc is enclosed, and by which the propelling power would be lost.
I therefore apply another curved flange to the first, of also a quarter of a circle,
by means of which the current will be delivered at right angles to the shaft of
the disc; the disc is fitted with curved armis, each being a portion of a cylinder,
and which arms at the same time form part of the generatrix of the screw in
the central passage; the said curved arms terminate nearly at tangents, at the
circumference of the disc or outer curved flange.
Instead of having the central passage open on both sides as above described,
one of the passages may be closed, and the curved flanges above described may
be dispensed with; as the centrifugal pump under such circumstances, if pro-..
perly constructed, will produce a vacuum within it, and by properly constructed
channels, I am enabled to guide the current in such a manner as to prevent it
striking against the disc opposite the orifice of the pump, and the unbalanced
pressure on the dise will be available for propelling traction. When a back-
ward and forward propelling traction is required;, two of such discs are to be
used and put in, rotary motion, either by a separate engine, or they may be
placed on the same shaft, provided they are fitted with suitable clutches or
friction brakes, so that only one of the discs revolves at the same time. The
discs are to be inclosed in a box containing water or other liquids, which by
the rotation of the disc produces the propelling action, either by means of
percussion or by vacuum.
I do not confine myself to the use of water as a propelling medium in this
apparatus, as other liquids may sometimes be used with more advantage; the

page_text: greater the specific gravity of the fluid employed, the smaller would be the size
of the apparatus for any given power; thus the specific gravity of water may be
increased by dissolving in it a salt, or by mixing it with other matters capable
of increasing the weight of the mass without reducing the moveability of the
fluid; or a composition of metal in a fluid state, such as that of tin, lead, and
bismuth, which melts at a low temperature, may also be used, provided the
apparatus is kept at the proper temperature to admit of the motion of the
melted metal.
These propelling apparatuses described may also be fixed at the stern or
bow; or at the stern and bow. at the same time, and placed transversely or .at
right angles to the keel of a vessel, for the purpose of steering or manoeuvering
such vessels.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed by
the said Charles Augustus Holm in the Great Seal Patent Office on the
14th August 1854.
TO ALL TO WHOM THESE PRESENTS. SHALL COME, I, CHARLES
AUGUSTUS HOLM, of 21, Cecil Street, Strand, in the County of Middlesex, Civil
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, beáring date the Fourteenth day of February, in the year of our
Lord One thousand eight hundred and fifty-four, in the seventeenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Charles Augustus Holm, Her special licence that I, the said Charles
Augustus Holm, my executors, administrators, and assigns, or such others as
I, the said Charles Augustus Holm, 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 PROPELLING," upon the condition (amongst others) that
I, the said Charles Augustus Holm, by an instrument in writing 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. ti

page_text: NOW KNOW YE, that I, the said Charles Augustus Holm, do. hereby
declare the nature of the said Invention, and in what manner. the same. is to
be performed, to be particularly described and ascertained in and by the
following statement thereof (that is to say) :-
The nature of my said Invention for improvements in propelling, consists in
the propulsion of bodies by means of an apparatus in which the propelling
power is entirely concentrated within such apparatus, and which being fastened
to the body to be propelled, I am enabled to give motion to vessels, .carriages;
or.other bodies entirely independent of the medium rail or gear usual for the
propulsion or motion of bodies.
The propelling power within the apparatus I obtain by the movement or
percussion of a fluid on curved plates or their equivalents, and in order to
obtain such propelling action I elevate a fluid or semi-fluid by any convenient
means to any required height within a suitable chamber, and if such height
be considerable; I in some cases submit the fluid to pressure by means of
allowing the air within such chamber to be compressed; and by means of
suitable constructed passages and valves I allow the fluid to be discharged on
a series of curved plates, such plates being by preference portions of a cylinder,
when the 'percussion of a fluid on such plates produces the propelling action;
the fluid escaping from the curved plates is immediately received within the
casing or chamber forming part of the apparatus, and elevated by suitable.
means, and for which purpose I by preference make use of my patent centri-
fugal screw pump; the percussion plates or their equivalent, and the screw'
pump or means for elevating the fluid, is enclosed within a suitable casing; the
whole forming the propelling apparatus, which, as stated, is fastened to the body
to be propelled.
On motive power being applied to work the screw pump, the fluid is.
elevated and discharged in the casing, and thus a continuous motion of the
same quantity of fluid is produced, by means of which arrangement I am
enabled to employ fluids of great specific gravity, and obtain a greater pro-
pelling power than by any other means. When it is required to produce a
backward as well as a forward propelling action, a double series of plates is
used; the screw pump is then placed between the two series, and by the closing
or opening of the valves for the admission of fluid to either the backing or pro-
pelling series of plates, a backward or forward propelling action is produced. "
My propelling apparatus may be produced under an infinite variety of
forms, according to the propelling power required or the nature of the body to
be propelled; thus for instance, instead of having the curved plates composed
of portions of a cylinder equal to one quarter of the circumference of such

page_text: cylinder, an apparatus may be produced with percussion plates composed of one
half of a cylinder; and when the apparatus is worked under a great pressure, it
will be necessary to break or diminish the length of the jets when they leave
the percussion plates, in order to prevent the jets from striking the casing or
other parts, by which the propelling action would be lost; and to diminish the
length or velocity of the jets, I allow them to strike against a series of angular
plates, by which the velocity of such jets becomes reduced before being
received by the centrifugal pump; or; instead of the angular plates, the jets
may also be allowed to strike against a series of round bars or iron grating,
which would produce a somewhat similar effect; and further; as another expe-
dient of diminishing the final velocity of the jets, I sometimes use a compound
percussion box, consisting of a combination of large and small quarter or semi-
cylindrical percussion plates, the percussion acting on the larger plates being
positive, and the percussion on the smaller negative, and the effective percus-
sion for propelling will only be equal to the difference of percussion produced
between the larger and smaller percussion plates. My apparatus may further
be modified so far, that instead of using the percussion plates in the form of
portions of a cylinder, they may be in the form of a disc or curved circular
flange, combined with the centrifugal pump, which gives motion to fluid acting
on the curved flange; and in cases where the velocity of the current be con-
sidérable, such velocity may be reduced by means of angular plates, composed
partly of a portion of a cylinder and partly a disc, or the velocity of the current
may be reduced by allowing it to strike against a grating of round iron bars;
the form of the casing will in this arrangement assume the shape of a cylinder,
and in cases where a backward or forward propelling action is required, two
curved percussion dises and centrifugal pumps would be necessary.
The
pamps are to be put in motion either by separate engines, or they may be
placed on the same shaft and within the same casing, provided they are fitted
with suitable clutches or friction breaks, so that only one of the
at the same time.
pumps revolves
.
DESCRIPTION OF THE DRAWINGS.
Drawing No. 1, Figure 1, is a longitudinal section through the apparatus;
and Figure 2 is a plan, partly in section, with the upper parts of the casing
removed. The same letters refer to similar parts in all the Figures and
Drawings, unless otherwise described.
Drawing No. 1, Figure 1, is a longitudinal section through the apparatus;
and Figure 2 is a plan, partly in section, with the upper parts of the casing
removed. The same letters refer to similar parts in all the Figures and
Drawings, unless otherwise described.
A is a casing or compartment of the apparatus containing the requisite
quantity of propelling fluid to be put in motion by the centrifugal pump. B is
my patent centrifugal screw pump; C is the shaft for working the sanie, and

page_text: to which any suitable motive power is to be applied. (The particulars of this
pump are fully described in my Patent of the Sixth of October, One thousand
eight hundred and fifty-three.) D is a closed chamber below the casing and
of which it forms a part, having two short channels, cach provided with a
throttle or equilibrium valve E and E'. F and F' are. bent passages, leading
the propelling fluid to the closed chambers G and G', into which the fluid rises
and compresses the air within the chamber. H, H, H, H, and H', H', H', H',
are the curved percussion plates, each a quarter of a cylinder and provided with
flanges, which they are fastened to the casing. I, I, I, I, and I, I, I, I,
are small half cylinders, which form part of and in addition to the percussion
plate of one quarter of a cylinder, which latter, may be remarked, is bent over
in a half circle on its upper edge, by which means, when several percussion
plates are put one close to the other, this half circle determines the spaces for
the discharge orifices, and at the same time it presents a suitable form for pre-
venting, contraction or derangement of the jets. K, K, are flanges of the
casing or apparatus fastened to the body to be propelled. L, L, are spindles
of the equilibrium valves, which pass through stuffing boxes on the casing; to
these spindles are attached levers or other suitable gear for moving the valves.
The action of the apparatus will easily be understood by supposing the valve E¹
to be closed and the valve E to be open, and by applying motive power to the
shaft of the screw pump B, the centrifugal action produced by the revolution
of the pump will cause the fluid in the casing A to pass up the bent passage F,
and partly fill the chamber G, and the fluid will then be discharged in jets
through the orifices M, M, M, M, and produce a propelling percussion on the
curved plates in opposite direction to the motion of the current, as shewn in
Figure 1. If the valve E be closed and the valve E! opened, a similar pro-
pelling percussion will take place in opposite direction, for the purpose of
backing by the discharge of the fluid through the orifices M', M', M', M',,on
the percussion plates II, II', H', H'. The percussion plates are of different
radius, in order, that each jet may be delivered freely and horizontally without
interfering with each other, and they will then take the curve of gravity due to
the head pressure, which in this apparatus is calculated for ten feet, when the
jets will take the form of delivery as shewn in Figure 1. N is a cover on the
casing, in order to fill the apparatus with fluid, and also to be able to put in the
screw pumps. O is a curved ring fitted to the casing; the lower edge of this
ring has a turned flange, against which the circumference of the central orifice
of the pump, works; the object of this ring is to facilitate the entrance of the
fluid to the pump, and also when this ring is lifted out, to be able to remove

page_text: the pump, if at any time required. P is a ring on the under side of the screw
pump, which works into another ring on the bottom of the chamber D, by
means of which the pressure of the fluid on the screw pump is removed, and
the small orifices Q, Q, bored on the pump in order that any leakage through
the circular rings P may be removed. The apparatus is drawn to a scale suit-
able for the propulsion of a vessel, but smaller apparatus may be constructed
on the same principle for the propulsion of carriages, locomotives, or other
bodies. I should, however, remark that certain dimensions, such as the length
of the casing A, should be determined by the. length of the jets due to the head
of discharge under which the apparatus is to be worked, so as not to strike the
casing, whilst the propelling power is depended on and determined by the area
of the discharge orifices and the specific gravity of the fluid employed, and
such power may be found by taking the weight of the column of fluid of which
the area of the discharge orifices is the base, and the length of it equal to the
head of discharge under which the apparatus is worked, and the weight of
such column is then multiplied by a co-efficient of percussion; to be determined
by practice, as such co-efficient will depend on the smoothness of the surface
of the percussion plates, and also of the proportions or ratio of the radius of the
percussion plate to the thickness of the jet employed. I have found that the
maximum co-efficient of percussion is produced when the radius of the per-
cussion cylinder is fifteen times the thickness of the jet; but in cases where it
would be objectionable to use such large dimensions on account of the space
required, I should remark that it is not necessary, in order to obtain a good
practical working co-efficient, to have the radius of the percussion cylinder
more than five to ten times the thickness of the jet.
I have now described the principle of my propelling apparatus sufficiently to
enable competent engineers to construct it under an infinite variety of forms
and modifications, according to the power required or the nature of the body to
be propelled, but in order to comprehend more clearly the extent of the prin-
ciple, I will now proceed to show a few of such modifications of form, or their
equivalent, in order to produce a similar or somewhat similar result:
Figure 3
shows a portion of my apparatus containing the percussion plates H, H, H, H,
which, in this arrangement are constructed to be of an equal radius of cylinder,
and in order to obtain the clearance for the delivery of the jets, each 'plate is
placed sufficiently below each other. In Figure 4 the plates H, H; H, a
also of an equal radius of cylinder, but somewhat less than a quarter of a circle,
by which the clearance for the delivery of the jets is obtained by allowing the
jets to be delivered at an angle to the horizon; and in Figure 5 the percussion
are

page_text: plates H, H, H, are so far modified that instead of being a portion of a cylinder,
they are flat or angular plates, by which the perpendicular direction of the jets
is changed into that of a horizontal direction.
Drawing No. 2, Figure 6, shows part of a similar apparatus as the one
described in Figure 1; the same letters have reference to similar parts,
but it is so far modified as to produce a somewhat similar result by simply
allowing the jets to be discharged into the casing A, through the orifices
M, M, M, M, when a propelling action will take place at H, nearly similar to
that on the curved percussion plates. Figure 7 shows part of the apparatus by
which only one jet is discharged through the orifice M into the casing A.
Figure 8 shows part of apparatus by which two jets. are discharged through the
orifice M, M, and a propelling percussion produced on the double curved plate
H, and H, each being a portion of a cylinder, and fastened in the passage F,
opposite the discharge orifice. Figure 9 shows an arrangement for dispensing
with the air chamber G, described in Figure 1, and a propelling percussion is
produced on the plates H, H; H; H, each being a' quarter of a cylinder, and
fastened into the passage F; by which means the current is divided into four
jets and discharged into the casing A, through the orifices M; M, M, M.
Figure 10 is similar to Figure 9, but discharges only one jet into the casing A,
and the propelling action produced at H, in the passage F. Figure 11 shows
an arrangement by which the thickness of the jets are adjusted so as to
encrease in the same proportion as the radius of the percussion plate, and thus
each jet will work under a uniform co-efficient of propelling, notwithstanding
the difference of the radius of the percussion plates H, H, H, H. Figure 12.
shows an arrangement for receiving the propelling action or senii-cylindrical
percussion plates; the current in passing through the passage F is divided into
four jets by 'the orifices M, M, M, 'M, and in running upwards produces a
propelling percussion 'on the plates H, H, H, H, and finally delivered into the
casing A. Figure 13 shows a similar arrangement, with one jet discharged
through the orifice M, and acting on one semi-cylindrical percussion plate H.
Figure 14 shows part of the apparatus, to which is applied a compound percus-.
sion box, or an arrangement of working a jet on several percussion plates, by
means of which the final velocity of the jet will be reduced, and by which I am
enabled to work the apparatus under a greater pressure, without the necessity.
of encreasing the length of the casing A; the jets on being discharged through
the orifices M, M, M, on the plates H, H, H, is allowed' to strike against
negative percussion plates. R, R, R, each of a'smaller radius of curve than the
positive percussion plates H, H, H, and which causes the jets to bend down
wards in a perpendicular direction; they are then allowed to strike against the

page_text: positive percussion plates S, S, S, and are finally discharged into the casing:A.
Figure 15 shows a similar arrangement, but instead of reducing the velocity-of
the jets by curved plates, they are, after having produced the propelling action
on the curved plates H, H, allowed to strike against the angular plates R, R¹,
and S, S', which produces a somewhat similar effect in reducing the final
velocity of the jets; and by the striking against the angular plates, the jets
become reduced into a kind of spray, of great thickness, as shewn in the Figure,
Drawing No. 3.
Figure 16 is a longitudinal section of an apparatus for working a
compound jet under a head pressure of forty fect. Figure 17 is a sectional
plan of the same, the same letters referring to similar parts as in Figure 1.
A is the casing containing the propelling fluid, and by the revolution of
the centrifugal screw pump B, the fluid is elevated into a cylinder D; on
the valve E being opened, the jet is discharged through the orifice M, and
strikes the semicircular percussion plate H, and having passed that semi-
cylinder, the velocity of the jet is reduced by allowing it further to strike
against the plate R, which forms a right angle with the bottom of the casing
A, and this causes the jet to go upwards when it strikes against the lower part.
of the passage F; the plate S forming a right angle with the passage F, causes
the jet to change its perpendicular direction into that of a horizontal; the jet
will then strike against the plate T, descend downwards, and finally change its
direction by means of the plate U, and thus be delivered into the casing A to
be received by the centrifugal pump B, and elevated. By closing the valve E,
and opening the valve E', a backing propelling action will take place on the
semi-cylinder II', and the velocity of the jets reduced by the plates R', S, T,
and U; the cover N in this case forms part of a cylinder which descends
downwards into the cylinder D, and by which means an air chamber is formed
in the apparatus at G. The centrifugal pump B is provided with a stationary
disc P, which is fastened or suspended to the cover N, by bolts for adjusting
the disc P to the upper surface of the pump, which is turned so as to form a
joint, and by means of which the pressure of the fluid on the pump is removed.
Small holes Q, Q, are bored in the pump, in order to draw away any fluid that
may leak through the joints of the disc P. Figure 18 shows a compound
percussion. box. composed of semi-cylinders; the jet discharged through the
orifice M on the semi-cylindrical plate H is changed in its direction by a semi-
cylinder R, of smaller diameter, and is then further allowed to strike against
the large semi-cylindrical percussion plate S, and finally discharged with a
reduced velocity into the casing A. Figure 19 shows a similar arrangement,
but the semi-cylindrical percussion plates are placed: one within the other;

page_text: the jet discharged through the orifice M on the plate H is changed in its
direction by the semi-cylinder R, when it strikes against the semi-cylindrical
plate S, and further changed in its direction by the semi-cylinder T, and finally
strikes the semi-cylinder U, when it is afterwards delivered in the casing A
of the apparatus.
Figure 20 shews a similar arrangement for reducing the final velocity of the
jet by angular plates or boxes H and S; the percussion on the plates R and T
in this Drawing are negative, and the percussion on the plates H, S, and U,
are positive, and the propelling percussion will only be equal to the difference
between the positive and negative percussion.
Drawing No. 4. In this Drawing is shewn an apparatus constructed on the
same principle as those described, but with an entire change in its form; the
casing in this apparatus assumes the shape of a cylinder, and the percussion
plate the shape of a disc or bent flange. Figure 21 is a cross section through
the apparatus. Figure 22, a longitudinal section; and Figure 23 shows the
percussion plate separate. A is a cylindrical casing, containing the requisite
quantity of propelling fluid, which is filled through the man-hole door D. B
and B are centrifugal screw pumps mounted on a horizontal shaft C. N and.
N' are end covers to the cylinders A, provided with stuffing boxes, through
which a tubular part of the centrifugal pumps passes. E and E' are discs
fastened to the shaft C, for working the pumps, and so arranged that when the
shaft turns in one direction the pump B only revolves, and if turned in the
opposite direction, the pump B¹ will revolve, and the pump B will remain
stationary, and this is accomplished by means of the discs E, E', and the
double armed crank F and F, which latter being fastened to the tubular part
of the pumps projecting through the levers N and N¹. The disc E and crank F
are shown separate in Figures 24 and 25. The crank F is provided with two
pins I and I, to which are fitted the short levers G, G. L, L, are friction
slides, fitted to a groove in the circumference of the disc E. The length of the
levers G, G, are so adjusted that it forms a sort of knee lever in combination
with the crank F, and thus, when the disc E revolves in the direction shown
by the arrow, the levers G, G, will cause a pressure on the friction slides .L, L,
by which means the double armed crank F and the pump B will be put in
rotary motion; and if now the shaft C be turned in the opposite direction, the
crank F and the pump B will become stationary, but the crank F¹ and the
pump B will be put in motion; the short levers G, G, are provided with a
small pin; on which the spring W presses slightly, in order to keep the friction
slides as near the circumference of the disc as possible, without causing any
pressure by the slides on the disc.
.

page_text: Having now described the means by which either one or the other of the
pumps B and B' may be put into a rotatory motion, the action of the apparatus
will easily be understood by supposing the pump B to revolve, and the pro-
pelling current discharged at the circumference of the pump; such current will
by its velocity cause a propelling percussion on the disc or curved flange H.;
this curved flange is generated by a quarter of a circle.and the jet; after having
passed, it would be delivered in the form of a hollow cylinder, and could be
immediately discharged into the casing A, provided the length of the casing was
calculated to answer for the head pressure under which the apparatus was
intended to be worked; but I have shown an arrangement for working a com-
pound jet, by which I reduce the velocity of the jet by angular discs calculated
to work a propelling current discharged at the circumference of the pump at
M, M, equal with a velocity corresponding to a forty feet head of discharge,
and thus the current, after having produced a propelling action on the curved
flange H, is allowed to strike against the flange R, R, of the cylinder A, when
its direction will be changed, and it will further strike against the cylinder T;
forming part of a casing that encloses the pump B; the cylinder T is provided
with a disc or flange S, which will cause the jet to be delivered into the casing
A, horizontally, in the form of a hollow cylinder, and at a velocity considerably
reduced in comparison to its initial velocity of discharge at M; the pump B
will by its revolution keep the current in motion, and produce a permanent
propelling percussion within the apparatus. On reversing the motion of the
shaft C, so that the pump B¹ will revolve, a similar propelling action will take
place on the curved flange H', for the purpose of backing. P, P, P, are pieces
or brackets, forming part of the discs S and S', for the purpose of supporting the
cylinders T and T' within the cylinder A; K, K, are beams to which the
apparatus is fastened, and such beams 'form part of the body to be propelled.
My apparatus may further be produced under a variety of other forms,
depending on the application of the motive power, and whether such power be
within or outside the casing; or an apparatus may be produced with cylindrical
or bent percussion plates in combination with' a centrifugal pump or pumps
working on a horizontal axis, or the pump or pumps may be working either
with a vertical or horizontal axis, combined with cylindrical percussion or other
plates, the axis of which may be in a vertical position; the casing of the appa-
ratus may also be considerably modified in its form, as in the cases of the
propulsion of iron vessels; suitable compartments may be built within the
vessels for the discharge or reception of the propelling fluid, and also for fixing
the percussion or other plates.
My propelling apparatus may also be constructed so as to be fixed at or

page_text: near the stern of a vessel, or one apparatus may be fixed at or near the stern
and another at or near the bow of the same vessel, and placed transversely .or
at right angles to the keel for the purpose of steering or manoeuvering such
vessels.
.
The fluid I propose to employ as a propelling medium in my apparatus is
water, but I do not confine myself to the use of that fluid, as in cases where
the object is to obtain a great propelling power within small dimensions
of apparatus, fluids of greater specific gravity would be preferable, and the size
of the apparatus would then for any given power diminish in proportion to the
specific gravity of the fluid employed. When the expense is of no consideration
mercury would be the best fluid to use; as having the greatest specific gravity,
and next to that would be a composition of tin, lead, and bismuth, of such pro-
portions known to melt at a temperature below the boiling point; but in this
case it will be necessary to keep the apparatus at a proper temperature by an
outer steam casing, or subject it to other means of melting, and it would also
be necessary to exclude the atmospheric air from the surface of the melted
metal, and admit in its stead steam or gases, in order to prevent the oxidation
of the metal. In using water, the specific gravity may be increased con-
siderably by dissolving in it common salt, or the water may be mixed with
lime, white lead, or other matters well known, and capable of increasing the
weight of the mass without reducing the movability of the fluid. I have found
that red lead, or the oxide and chloride of lead, commonly called patent or
Montpellier yellow, when ground with olive oil or water, would produce a
suitable working fluid, having a specific gravity of from 3 to 4 times that of
water.
Having now particularly described my propelling apparatus with various
modifications and equivalents for the propulsion of bodies, I claim as my
Invention,―
First, the discharging jets of fluids into a box, casing, or other suitable com-
partment attached to or built on or within the body to be propelled..
Secondly, to propel bodies by means of percussion of a fluid on curved plates
or their equivalents, as above described.
Thirdly, the combination of parts into a propelling apparatus, by means of a
centrifugal pump or pumps, or any suitable equivalent for the elevation of
fluids, acting by means of percussion on plates, and discharge such fluid into a
compartment or casing attached to or built on or within the body to be pro-
pelled, and also such modifications or their equivalents, as above described.
Fourthly, the use of fluids having greater specific gravity than water for the
propulsion of bodies.

page_text: Fifthly, the placing and working the propelling apparatus transversely to the
keel of a vessel, for the purpose of steering or maneuvering such vessel.
In witness whereof, I, the said Charles Augustus Holm, have hereunto set
my hand and seal, this Fourteenth day of August, in the year of our
Lord One thousand eight hundred and fifty-four.
Witness,
JNO. ALCOCK.
C. A. HOLM. (L.S.)