AN INSTRUMENT FOR MEASURING THE STEERAGE-WAY OF VESSELS, AND THE RAPIDITY OF CURRENTS OF WATER AND AIR, APPLICABLE TO VENTILATING SHIPS AND RAILWAY CARRIAGES
Year: 1853

page_text: LETTERS PATENT to Frederick William Campin, of 156, Strand,
in the County of Middlesex, Patent Agent, for the Invention of
"AN INSTRUMENT FOR MEASURING THE STEERAGE-WAY OF VESSELS,
AND THE RAPIDITY OF CURRENTS OF WATER AND AIR, APPLICABLE TO
VENTILATING SHIPS AND RAILWAY CARRIAGES."-A communication
from Messrs. Owerduyn and Droinct.
Sealed the 9th September 1853, and dated the 9th March 1858.
PROVISIONAL SPECIFICATION left by the said Frederick William
Campin at the Office of the Commissioners of Patents, with his
Petition, on the 9th March 1853.
I, FREDERICK WILLIAM CAMPIN, do hereby declaro the nature of the
said Invention for "AN INSTRUMENT FOR MEASURING THE STEERAGE-WAY
OF VESSELS, AND THE RAPIDITY OF CURRENTS OF WATER AND AIR, APPLICABLE
TO VENTILATING SHIPS & RAILWAY CARRIAGES," communicated to me
from abroad by certain foreigners, viz., Messrs. Owerduyn & Droinet,
to be as follows:-
This Invention refers to, 1st, To the application of hydrodynamic,
and more especially of negative pressure, as a means of measuring the
speed of vessels and currents; 2nd, To the use and arrangement of

page_text: metallic plates or elastic tubes for the purpose of determining the results
of this pressure.
Negative pressure is produced either by cylindrical or by double-
coned (commonly called "Venturi's ") tubes. Their longitudinal section
represents two truncated concs united at top. They will generally be
used in preference to the cylindrical tubes, without, however, entirely
superseding them. A single tube to each vessel is sufficient for the
proposed object, but for greater security two would be preferable. They
are placed parallel to the keel on each side of the ship, and under the
level of the water, and fixed securely, but so as to allow of their being
easily removed from the water when required to be examined for repair.
or the removal of adhering substances.
This tube is in connexion with a mercurial syphon or manometer,
and in the mercurial syphon the rising and falling of the mercury therein
is the means of indicating the speed of the vessel or the current.
Theso Venturi tubes may be used for the measurement of the spec
of currents of water and air, and adapted to the ventilation of ships and
metallic plates or elastic tubes for the purpose of determining the results
of this pressure.
Negative pressure is produced either by cylindrical or by double-
coned (commonly called "Venturi's") tubes. Their longitudinal section
represents two truncated cones united at top. They will generally be
used in preference to the cylindrical tubes, without, however, entirely
superseding them. A single tube to each vessel is sufficient for the
proposed object, but for greater security two would be preferable. They
are placed parallel to the keel on each side of the ship, and under the
level of the water, and fixed securely, but so as to allow of their being
easily removed from the water when required to be examined for repair.
or the removal of adhering substances.
This tube is in connexion with a mercurial syphon or manometer.
and in the mercurial syphon the rising and falling of the mercury therein
is the means of indicating the speed of the vessel or the current.
These Venturi tubes inay be used for the measurement of the speed
of currents of water and air, and adapted to the ventilation of ships and
railway carriages.
:
SUPPLEMENTAL PROVISIONAL SPECIFICATION.
"A."
I, FREDERICK WILLIAM CAMPIN, do hereby further declare the nature
of the said Invention for "AN INSTRUMENT FOR MEASURING THE STEERAGE-
WAY OF VESSELS, AND THE RAPIDITY OF CURRENTS OF WATER AND AIR,
APPLICABLE TO VENTILATING SHIPS AND RAILWAY CARRIAGES," to be as
follows, as regards ventilation:-The apparatus described may be made
applicable to ventilation thus: In ships the tube mentioned in the
Provisional Specification will be immersed in the water at any part
of the ship, with its smaller end pointed-forwards. It has, like tho
other tubes, at its smallest section, a connecting pipe. This tube or
pipe ought to be flexible. The end of it opposite to that connected
with the coned tube is placed in the space whence the foul air is to be
expelled. These arrangements being made, the mere progress of the
vessel eflects the required ventilation.
In railway carriages a tube of the largest dimension must be placed

page_text: aspiration, which wil begin to take effect the moment the train starts.
The above will, with attention to the proper constructive arrangements,
effect the purpose of ventilation in the above cases.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said Frederick William Campin, in the Great Seal
Patent Office, on the 9th September 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
FREDERICK WILLIAM CAMPIN, of 156, Strand, in the County of Mid-
dlesex, Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Ninth day of March, in the year of
our Lord One thousand eight hundred and fifty-three, in the sixteenth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Frederick William Campin, Her special licence
that I, the said Frederick William Campin, my executors, adminis-
trators, and assigns, or such others as I, the said Frederick William
Campin, 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
MEASURING THE STEERAGE-WAY OF VESSELS, AND THE RAPIDITY OF
CURRENTS OF WATER AND AIR, APPLICABLE TO VENTILATING SHIPS AND
66
RAILWAY CARRIAGES," (a communication from Messrs. Owerduyn and
Droinet, of Paris), upon the condition (amongst others) that I, the
said Frederick William Campin, 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.
NOW KNOW YE, that I, the said Frederick William Campin, do
hereby declare the nature of my said Invention, and in what manner

page_text: the samo is to be performed, to be particularly described and ascertained
in and by the following statement:-
This Invention consists, first, in the application of hydrodynamic, and
more especially of negative pressure, as a means of measuring the speed
of vessels and currents.
Second, in the use and arrangement of metallic plates or clastic
tubes for the purpose of determining the results of this pressure.
Tho fundamental principle of this apparatus, to which is given the
name of Velocimeter, was established about a century ago by Daniel
Bernoulli. Hitherto it has been but rarely applied in practice, and it
is not now purposed to develop its various properties, but merely to
indicate it as the source of the theory.
Negative pressure is produced either by cylindrical or by double-
coned (commonly called "Venture's" tubes). Their longitudinal section
represents two truncated cones united at top. They will generally be
used in preference to the cylindrical tubes, without, however, entirely
superseding them.
The principal part of the Velocimeter consists of a double-coned tube
of any metal (as represented in Plate 1st, Figures 1, 2, and 3), under
the letter A. The first figure indicates one of these tubes in correct
proportions, about one third of its natural size. When this tube is
formed of sheets of copper it should be incased in wood, in order to
facilitate its adjustment on a frame, which I shall notice presently.
But this precaution is not indispensable, as may be seen by referring to
Figures 2, and 3.
A single tube to each vessel is sufficient for the proposed object, but
for greater security two would be preferable. They are placed parallel
to the keel on each sirle of the ship, and under the level of the water,
securely fixed, but so as to allow of their being easily removed from the
water when required to be examined for repair, or the removal of
adhering substances. If but one tube be employed it may be advan-
tageously fixed on the larboard or starboard side, but would bo better
placed forward, in which case it must be forked at the posterior extre-
mity (Plate 2nd, Figure 6), the same sectional proportions being always
maintained, and care taken that no difficulty be incurred in lifting it

page_text: out of the water. The diving tube is firmly attached to a frame formed
of bars of iron. This frame must be so constructed that, first, the axis
of the tubo under water be parallel with the keel; 2nd, that the whole
apparatus remain inmoveable and secure from accidents during the pro-
gress of the vessel; 3rd, that the tube can be easily withdrawn from
the water to be examined. For these purposes several mechanical means
may be employed, but it will be sufficient to mention the following,
which have been found sufficient in practice. The frame which supports
the tube may be made to revolve on two points, A and B (Plate 2,
Fig. 7.) so that the tube shall describe 180° on a plane perpendicular
to the side of the ship, or else it may be made to turn on a single
point A, Fig. 8, the tube describing an arc of 90° on a plane parallel
to the ship's side; the essential object, whatever may be the mechanical
means to attain it, is to secure the tube and frame so as to maintain
them firmly in the conditions above described in spite of the action of
the waves, or the disturbance occasioned by the working of the vessel.
The double-coned tube (Plate 1, Fig. 1,) is pierced by a small hole C,
in its smaller section B. At this point it is met by a metal pipe which
communicates with the interior of the tube, through the original C,
the internal diameter of which ought not to exceed one centimeter
(some millimeters would suffice). This pipe branching from the tube
is attached to one of the bars of the frame which bears the tube (Plate 2,
Fig. 7, C,) so as to be protected from any external cause of injury. This
metal pipe being forced to move in obedience to the impulse given to
the frame every time that it is necessary to remove the tube from the
water, or to submerge it, and at the same time being throughout
hermetically closed, it will be indispensable to fit it with a cock or
joint, either at the point B, Fig. 7, or at the point A, Fig. 8, so that
the motion of the frame may be entirely free without the necessity of
unscrewing any part of the gear. Proceeding from the frame, the
pipe extends to one of the branches of the mercurial syphon G (Plate)
Fig. 2,) or else to the manometer composed of clastic plates G, Fig. 3,
so as to keep up a direct and uninterrupted communication between
the smaller section of the diving tube, and the column of mercury
(should it be intended to act on the syphon), or tho manometer, if the

page_text: latter be required to operate. The plate manometer completes the
apparatus, and its application will be more frequent than that of the
mercurial syphon, especially in navigation; for, once fixed to the vessel
and placed in communication with the diving tube, it acts incessantly
under the eye of the helmsman, and consequently attains completely
the end had in view in forming the instrument. I cannot, however,
dispense with describing separately the portions of the apparatus
represented in their greatest simplicity by the Fig. 2, and 3, Plate 1.
DESCRIPTION OF THE MERCURIAL SYPHON.
The simple syphon (Plate 1st, Fig. 2nd), is composed, 1st, of a
diving tube; 2nd, of a pipe which causes it to communicate with the
syphon 3rd, of the syphon itself. The double-coned tube being
submerged, with its smallest exterior orifice opposed to the current (the
velocity of which is to be measured), being turned towards the prow of
the ship parallel with its side. the action of the current produces in the
smallest section of the tube a void, which, acting through the pipe of
communication on the column of quicksilver in the syphon, marks by
its aspirations a rise of the mercury. This motion increases or dimi-
nishes according to the strength of the current or the speed of the
vessel; and the displacement of the mercury, measured by a graduated
scale. shows the corresponding celerity of the steerage-way. This
suction, determined by the form of the diving tube in any current, is. as
may be perceived, the fundamental principle of the system. Instead of
the simple syphon the manometer may be used (Plate 2, Fig. 9), of
which the following is a description:-A, prolongation of the communi-
cating tube abutting in the chamber C, C. B, B, bent tube of glass,
one end of which is left open, the other being cemented in an opening
at the botton of chamber C. This apparatus may be fixed at the part
of the box C, (Plate 1st, Fig. 3rd,) and secured on the frame which
supports the diving tube. On submerging this tube, and fixing the
frame D, D, D, to the side of the ship by the hooks F, F, F. taking
care to oppose the smallest orifice of the tube to the current, a glance
will show the rise of the mercury, and on the scale (Plate 2, Fig. 9.)
the corresponding velocity. But this mode of proceeding has its incon-

page_text: veniences; the principle of which is with reference to the log, which
must be thrown into the water to measure the rate of going. The
same objection would apply to the velocimeter, such as we have just
described it, which would act only at the moment when the diving tube
is immersed. For this reason we securely fix on one hand the frame:
and its tube, and on the other in the chamber containing the barometer,
either the syphon or the mercurial manometer and its scale, and we
make them communicate by a pipe of lead or of any other metal.
The apparatus being thus able to accommodate itself to all the windings
of the vessel, its operations under these conditions will be perfect.
DESCRIPTION OF THE METALLIC OR ELASTIC PLATED MANOMETER.
This instrument may be placed upon the deck under the same
binnacle as the mariners compass, and in view of the steersman. It is
a circular box (Plate 1, Fig. 4), furnished with a metallic plate D, D,
surmounted by a dial on which a needle moves, retrograding from its
fixed point, in proportion to the speed of the vessel. The interior of
the box communicates with the pipe which terminates at the diving
tube. The suction determined by the steerage-way forces the plate
D. D, downward, according as the velocity increases: This depression
in the centre of the plate, which has a vertical direction, is transformed
into a horizontal and circular movement, fully developed by a system of
levers, which shall be explained; this motion communicates its action to
the needle of the dial. (Plate 1st, Fig. 4), A, vertical projection of
the box; B, horizontal projection; C, vertical projection of the interior
support; H, principal lever; I, the point on which it rests; G, steel
rod, which bears upon a support, also of steel or agate, on the back of
the principal lever; K, spring supporting the head of the great lever
destined to bring it to its original position when the exterior pressure
ceases or diminishes; P, Q, small lever, the arms of which form a
right angle; R, the point on which it rests; O, bar which transmits
the motion of the large to the small lever; T, chain attached to the
longest arm of the small lever, and rolled around the axis V, upon
which the needle is fixed; W, spiral spring to bring the needle to its

page_text: primitive position. V (Figure 4), part that directs the motion of the
needle; N, segment of a circle to determine the motion of the chain.
To render the susceptibilities of the manometer more accurate, instead
of employing a single plate, a box composed of two plates may be used,
and if necessary many boxes fixed in their centre, and communicating
with each other (Plate 2nd, Fig. 10). The exterior shapo of the
manometer is quite optional. The manometer just described has only
one plate; it is, as well as the levers, correctly proportioned and dimen-
sioned to correspond with the movement of a column of mercury from
0° to 70°, and is capable of measuring the greatest and the smallest
velocities. The needle has a length of about 0 15, so that the divi-
sions and subdivisions of the dial are sufficiently distinct. When a vessel
does not exceed a certain speed, the arc of the circle may be increased
to correspond with a given velocity, in order that the figures of the
divisions may be more easily read at a distance.
The whole apparatus understood by the name of velocimeter, consists,
therefore, 1°, of a (Venturi) tube submerged parallel to the keel of a
vessel, the smaller aperture turned towards the current: 2nd, of a
frame of iron bars supporting the latter, and moving on the swivel
principle, so as to be easily withdrawn from the water; 3°, of a pipe
connecting the diving tube at its smallest section with the manometer;
4, finally, of the manometer itself, whether composed of the syphon,
or pipes, or of elastic plates.
One of these manometers does not exclude the other; they enn work
together. or separately it would be even well to have both on board
large vessels, as they mutually complete and regulate each other. The
mechanism described for transmitting the motion from the centre of
the metallic plates to the axis of the needle, has nothing in it of an
exclusive character, being increly accessory to the Invention; the
intrinsic value of which would be no ways affected by any modification
of said mechanism, or even by the substitution of any other means for
transmitting the movement. Such indeed would be indispensable if it
were thought preferable to use, instead of the metallic plates, the elastic
tubes of Bourdon, which under certain conditions would advantageously
aflect the same purpose.

page_text: If, with regard to navigation, we have more particularly dwelt on the
metallic plates, it is because they are less subject to the vibrations
which the motion of the vessel would unquestionably impart to the
elastic tubes, thereby affecting the accuracy of their operation.
APPLICATION OF THE VELOCIMETER TO THE MEASUREMENT OF THE SPEED
OF CURRENTS OF WATER AND of Air.
The double-coned tube is plunged in the current, whose velocity is to
be ascertained with its smaller end forward, that is, opposed to the flow.
If the latter be slow, and the syphonmanometer be used, water must be
substituted for mercury, in order to mark more sensibly the difference
of pressure. If the platemanometer be preferred for the experiment, it
will be necessary, in order to increase its effect, to add one or two plates
as we have above suggested. The connecting pipe B, Plate 1°, Fig. 3°,
must be provided with a graduated scale, commencing at the centro
of the diving tube, to denote to what depth it is immersed, in order to
determine the velocities at different depths, and thus to obtain the
mean velocity at any section of a river or canal. To determine the
speed of winds or currents of air, no use can be made of the manometer
acting by quicksilver or water; for, considering that the specific gravity
of air is seven hundred and seventy times less than that of water, it is
obvious that the most rapid currents of air could not produce a dis-
placement of water sufficiently marked to admit of accurate subdivisions
indicating the various degrees of velocity of aeriel currents; morcover
the column of water would never be at rest; it would be subject to the
sudden and incessant variations of the atmosphere, and would afford
but scanty and uncertain indications. This disadvantage of the liquid
manometer is indeed common to all instruments employed to measure
the velocity of wind, which is never constant. In, order, therefore, to
determine this velocity, recourse must be had to the metallic manometer,
and to ensure its effectiveness it should be fitted with double and triple
boxes to augment its accuracy.
It will be also necessary to increase the suction power of the diving
tube by doubling or tripling its dimensions, and by introducing into it
a second smaller tube, so placed as that its anterior orifice should

page_text: receive the air precisely at the point of the smallest section of the
larger tube, as indicated by (Fig. 12, Plato 2nd). The connecting pipe
branching from the tube abuts on point A. The velocity of a current
of air may likewise be determined by combining the effect of a
velocimeter with that of a barometer on the syphon principle.
principle. For
this purpose the two instruments must be placed in connection by
means of a double-branched cock. One of the branches being left
open, the barometer shows the state of the atmosphere; but if it bo
closed, and the other branch, be opened, communicating as it does
with the tube plunged in the current whose velocity is to be ascer-
tained, there will ensue a motion in the column of the barometer, the
inspired liquid will be displaced, and the space it traverses will be the
relative measure of the speed of the current.
By means of these several combinations a sufficient amount of
variations will be obtained to be easily noted; and to certify the result
of the experiments, Figure 12, Plate 2, indicates how the instrument
may be made portable for mining purposes. The manometer 13, is
immediately fixed on the tube, which is placed in the gallery where the
degree of ventilation is to be ascertained.
receive the air precisely at the point of the smallest section of the
larger tube, as indicated by (Fig. 12, Plato 2nd). The connecting pipe
brauching from the tube abuts on point A. The velocity of a current
of air may likewise be determined by combining the effect of a
velocimeter with that of a barometer on the syphon principle. For
this purpose the two instruments must be placed in connection by
means of a double-branched cock. One of the branches being left
open, the barometer shows the state of the atmosphere; but if it bo
closed, and the other branch, be opened, communicating as it does
with the tube plunged in the current whose velocity is to be ascer-
tained, there will ensue a motion in the column of the barometer, the
inspired liquid will be displaced, and the space it traverses will be the
relative measure of the speed of the current.
By means of those several combinations a sufficient amount of
variations will be obtained to be easily noted; and to certify the result
of the experiments, Figure 12, Plate 2, indicates how the instrument
may be made portable for mining purposes. The manometer B, is
immediately fixed on the tube, which is placed in the gallery where the
degree of ventilation is to be ascertained.
APPLICATION OF THE VELOCIMETER TO THE VENTILATION OF SHIPS AND
OF RAILWAY CARRIAGES.
To ventilate any part of a ship it will be necessary to employ a pipo
of about one meter in length, in the proportion shown in Fig. 11,
Plate 2nd. It is furnished with a hook at each extremity, to which is
attached a cord or a chain.
When it is to be used it must be inmersed in the water at any part
of the ship with its smaller end pointed forwards. It has, like tho

page_text: arrangements being made, the more progress of the vessel effects the
required ventilation.
This method of ventilation may be usefully combined with that in
ordinary use, which is to infuse, by means of a canvass funnel, fresh air
from the deck into the interior of the vessel. This latter contrivance
is imperfect, inasmuch as it wants the power of exspiration in its
action. Whereas our apparatus operating solely on that principle,
and being also adequate to insure a good ventilation, would the more
effectually become the complement of the ventilating process hitherto
employed. Its extreme simplicity morcover destines it to render vast
services to the marine, especially on board ships of war and transports,
in which, according to sanatory requirements, two or four tubes might
be used. Finally, the same apparatus might, in certain cases at sea, be
availed of for pumping water.
To ventilate railway carriages, a tube of the largest dimension (say
one meter) must be placed on each carriage, within which will be a
communicating pipe of aspiration, which will begin to take effect the
moment the train starts. This pipe must communicate with a tube
by a cock or some connecting medium, by which means it may be
turned in the direction of the train, so that its smaller orifice may
always point towards the tender. Instead of the cock or elastic
connection the connecting pipe might be shaped like a truncated conc,
and exactly fitted to another cone fixed at right angles on the tube,
taking care to leave between those two cones an opening which would
draw the air in the carriages to the smallest section of the tube; but
these arrangements always involve the inconvenience of being obliged
to turn the tube at each change of direction. To obviate this we
recommend a cylindrical instead of a conical tube. This tube (A,
Fig. 5, Plate 1st,) has at each of its extremities a truncated cone
moving on hinges, and inserting itself in the interior of the tube
according to the direction of the train. Two other pipes C, C, support
the tube, and convey to it the air which they aspire from the carriages.
This aspiration increases with the velocity of the train.
Advantage might again be taken of this apparatus to measure this
velocity, were it necessary. At all events it would prevent accidents,

page_text: most of which proceed from the excessive rapidity with which engineers
start their trains.
For this purpose it would be only necessary to sit up in the
conductor's sentry box, or in the carriage occupied by the inspector,
and under his eye, a manometer which should exactly indicate the
maximum rate of speed allowed by the regulations, and this mode of
control would be the more ellicacious, as it would be unvarying.
Having now described the nature of the said Invention, and in what
manner the same is to be performed, I further declaro that I claim
the said Invention as herein-before set forth and described.
In witness whereof, 1, the said Frederick William Campin, have
hereunto set my hand and seal, the Ninth day of September.
in the Year of our Lord One thousand eight hundred and fifty-
F. W. CAMPIN. (L.S.)
Signed and sealed in the presence of
D. McNISHI,
Patent Office, 156, Strand.