IMPROVEMENTS IN THE METHOD OF MEASURING HEIGHTS BY MEANS OF A NEW APPARATUS
Year: 1877

page_text: LETTERS PATENT to Sydney Pitt, of Sutton, in the County of Surrey, for the
Invention of "IMPROVEMENTS IN THE METHOD OF MEASURING HEIGHTS BY
MEANS OF A NEW APPARATUS." A communication from abroad by Nicholas
Yagn and Lewis Survillo, both of Moscow, Russia.
Sealed the 13th October 1877, and dated the 9th August 1877.
PROVISIONAL SPECIFICATION left by the said Sydney Pitt at the Office
of the Commissioners of Patents on the 9th August 1877.
SYDNEY PITT, of Sutton, in the County of Surrey. "IMPROVEMENTS IN THE
METHOD OF MEASURING HEIGHTS BY MEANS OF A NEW APPARATUS." [A com-
inunication from abroad by Nicholas Yagn and Lewis Survillo, both of Moscow,
Russia.]
The object of the Invention is the application of hydrostatic pressure to levelling,
and the construction of an apparatus called "manometrical altimeter," destined for
ascertaining the relative height of objects or of certain points in localities in cases
where direct measuring is difficult or even impossible.
. Compared with the apparatus already in use for the same purpose
the " mano-
metrical altimeter" offers among others the advantage of considerably simplifying
the solution of problems in levelling, and of being adaptable even to such cases
where the other apparatus are found inefficacious.
The construction and action of the manometrical altimeter are based on the well-
known hydrostatic law, according to which the pressure produced by a column of
liquid upon the sides of a vessel depends neither on the form nor on the dimensions
of the vessel, but merely on the height of the column, and the density of the liquid
itself.
Taking any reservoir A, and connecting the same by a flexible tube C with any
pressure pressure gauge, as, for instance, an open mercury manometer B, and the
flexible tube C and reservoir A being filled with a liquid, water, for instance, the
indications of the manometer B, will according to the afore-mentioned law only show
ID 11

page_text: =
the relative height where the reservoir is placed; the diameter of the flexible
tube C, its length and shape, the nature of its sides, as well as the greater or lesser
height of placing the intermediate parts of the tube, will have no influence whatever
upon the indications of the manometer. By this fact it becomes evident that when
the inercury manometer B is in a fixed and stable position, its indications will only
change in case of the reservoir A with the liquid being moved in vertical direction,
and the changes will strictly correspond to the vertical motion of the reservoir A.
Admitting the reservoir A be placed at a certain height H, the indication of the
manometer B will be h. If we move the reservoir A to H¹, the indication of
the manometer will change from h to h + a, giving the following proportion: H:
(H+ H³) h (ha); hence, H¹
is a constant quantity,
× a. Here,
7
and is fixed by experience once for all for every apparatus. Consequently, for
This
ascertaining the quantity H', we want only to ascertain the quantity a.
quantity is the difference between two consecutive indications of the manometer B,
which are obtained by simple counting on the scale of the manometer.
this very combination are based the construction and action of the manometrical
altimeter.
=
H
II
On
It is easily understood that instead of an open mercury monometer B, any
other pressure gauge may be employed, for instance, a condensed air manometer,
Bourden's metallic manometer, etc.; and the flexible tube C and reservoir A may be
filled, instead of with water, with alcohol or any other convenient liquid. This Inven-
tion consisting principally in the application of hydrostatic pressure for measuring
of height by means of any pressure gauge, it will be sufficient to describe
one of the modes of application, viz., the one affording the greatest accuracy in
measuring.
The manometrical altimeter, the construction whereof is shown in the Drawings
hereto annexed, consists of three main parts, viz., the manometer, the reservoir, and
the flexible tube connecting the same.
Figure 1 represents the front view of an open mercury manometer B, set into or
otherwise fixed to the small wooden board E.
Figure 2 is a view of the hind or interior surface of another board E', destined
to be put on the first, and to serve for preserving the manometer from being
damaged..
Figure 3 is a side view of the boards of the apparatus put together, and containing
the manometer B.
Figure 4 a front view, and Figure 5 a side view of a moving comb-like
scale for counting the indications of the manometer, as hereafter particularly
described.
:
Figures 6 and 7, the front and back view of the complete manometrical apparatus
provided with the comb-like scale, and their appurtenances.
Figure 8, a side view of the apparatus hanging on the support.
Figure 9, a vertical section of the reservoir A, provided with the flexible tube C.
Figure 10 shows one of the modes proposed for keeping the apparatus in a vertical
position.
Figures 11 and 12, the front and side views of a micrometrical screw serving for
accurately counting the indications of the manometer B.
Figure 13, a view from below of the board E.
Figure 14, a transverse section of the apparatus along. the line 1-2, in Figure 6.
As may be seen in the Drawings the manometer B itself consists of the bent
glass tube a, a, of which one end a is open, and the other at, being considerably
shorter, is widened out in the shape of a small cup b, placed at about half the height
of the knee a.
J
The diameter of the cup 6 is made about four times as large as the inside of the
tube, and its capacity a little more than that of the whole canal of the tube.
b may be of iron or of glass, with a metallic rim or lid on top, as shown
in Figure 1. From the lip of the cup b. is passing a crooked pipe c, at the upper
The cup

page_text: bent of which is the branch c¹, provided with the air tap d, and to the end of the
pipe c is fixed the free end of the flexible tube C (Figure 9).
For levelling not requiring particular accuracy may be employed a mercury
manometer without the cup b; but in order to diminish the chances of errors,
it is required in such case to determine the position of mercury in both
knees, while in using the manometer with the cup it is determined only in the
knee a.
The boards E, E¹, placed together conveniently, and fixed to each other by screws
or some other way, form a case to the manometer which is placed in the metallic
comb-like scale e (Figures 4 and 5).
The scale e can be moved up or down by means of the micrometrical screw e¹.
For this purpose, after placing the wooden case with the manometer, there is fixed
on the upper part of the scale e, by means of the screws e and es, the cross piece e²
with a nut screw (Figures 5, 11, and 12), through which passes the screw e¹,
turning in a fixed frame e³, encased in the corresponding cavity e of the
board E¹ (Figure 2). The screw e when turning presses against the metallic
plate e³, which is kept in its place by the screws e10 and e¹1 (Figures 11 and 12).
The pitch of the screw e¹ is equal to one millimeter; the circumference of the
head es of the screw is divided into 50 equal parts, and resting on the fixed disc eº,
provided with a vernier or nonius.
The motion of the scale e is guided by the pegs f which are fixed to the boards
E, E, and passing through corresponding spaces of the scale e (Figures 6 and 7).
The three guiding pegs f may be reduced to two (upper and lower) or even one
below, since the screw e¹ itself passing through the cross piece e² inay serve as a
guide above. Besides, it is evident that the fixed disc e with the vernier and the
micrometrical screw e¹ duly fixed to the moving scale e, with its frame and constant
scale can be placed on top of the apparatus, or in any other convenient place, for
instance at the very bottom of the apparatus. By this construction the motion of
the comb-like scale e, and consequently, the indications of the manometer B, can be
exactly noted up to 1/500 millimeter.
For observing the level of mercury in the knees of the tube a, a¹, there are clefts
or rifts a², a³, cut through both wooden boards E, E¹, (Figures 2 and 14), about
3m wide, the first of which is about as long as the whole length of the tube a,
and the second equal to the size of the cup b at the end a¹. These clefts are shut
outside by the comb-like scale e, so as to shine through the spaces of the comb, as
shown in Figures 6 and 7. It is evident that, looking through these spaces, the
light will pass only through those parts of the clefts a², as, that are corresponding
to the parts of the tube a and cup b, not occupied by mercury.
When a mercury manometer without the cup b is used the length of the knee a¹
is made equal to the length of the knee a, and the length of the cleft or rift a³
equal to the length of the cleft a². In this case it would be preferable to make the
scale e not comb-like, but like a rectangular tube or case surrounding the wooden
boards E and E from all four sides, the cuttings 1, 2, 3, etc., (Figure 6) being made
wide enough to cover the two clefts or rifts a² and as for determining the position
of mercury in both of the knees.
The comb-like scale e is cut out in such manner as to place the upper edges of
the spaces at an exact distance of a certain number of centimeters from each other.
Besides, on one of the longitudinal ribs of the frame e3 (Figures 6 and 12) of the
micrometrical screw e¹, divisions of one inillemeter are marked at a length a little
more than the distance between two contiguous spaces of the comb e. Along these
divisions the prominence b¹ (Figures 4 and 6) of the scale e noves in such manner
that the position of the scale e can always be exactly determined by means of the
line 6 marked on this prominence. The spaces of the comb-like scale, for more
convenience, are numbered 1, 2, 3, 4, etc. As it is not required, for levelling
according to the method, to know the absolute height of the mercury column, and
merely wanted to know the changing thereof, i.e., the difference between two
succeeding indications, it needs no particular accuracy in placing the comb relating

page_text: to the wooden boards of the apparatus, and only requires that the distance between
the upper edges of the spaces should be strictly invariable.
The counting of the manometer's indications by means of the comb-like scale e
is performed as follows:Looking towards the light through the teeth of the comb
we remark at once the light shining through the first space above the mercury in
the part a of the tube, let us say it be the eleventh space from below. Raising the
scale e by means of the micrometrical screw e¹, and observing the 10th space, which
as yet lets no light pass, we remark the moment when the first ray of light is
passing through the same; at this moment the turning of the screw e¹ is stopped,
because the appearance of light proves that the upper edge of the space 10 is level
with the surface of the mercury in the knee a of the manometer B. Observing
on the divisions of the frame e³ the number of millimeters the scale e was raised,
and on the vernier the part of turn given to the head e, the height of mercury in
the knee a of the tube is exactly ascertained. If, for instance, the distance between
the upper edges of the spaces is two centimeters and the 10th space had to be
raised three millimeters, and besides the screw head e5 wanted turning for 25-3
divisions, the height of the mercury is 203 253 m/m or 203-506 millimeters.
For levelling not wanting minute exactness the indications of the manometer
may be counted by means of an ordinary scale provided with a vernier, and other
requisites generally used. In this case, however, the manometer B is fastened to
the scale immovably.
The manometrical apparatus is suspended by the eye h (Figures 7 and 8) at the
hook of the stay g of the support D. Although the manometer thus suspended
will serve to take a vertical position this position will not be strictly determined
nor sufficiently stable, because the slightest draught of air or contact will shake
the manometer. For removing this inconvenience the application of the plummet k
and the friction shoes 1, 1, (Figures 1, 3, and 8) is proposed. The plummet k is
placed in the glass tube m. The metallic bottom n of this tube has in the centre
a conic point o. The line of the plummet is fastened in the centre of the
metallic lid p, covering the tube m, of which about one-half is filled with alcohol,
transparent oil, or some other convenient liquid. The plummet / being in the
liquid will settle incomparably sooner than without the same. For observing the
position of the pluminet k the board E¹ is provided with the cleft a Sideways
the plummet is perfectly visible. The tube m, with the plummet k, can of course
be fastened at any place that may be thought convenient outside of the case E, E¹.
The friction shoes 1, 1, are fixed to the ends of the rods r, r, and provided with
a somewhat convex basis. The rods are moving in the guiding eyes 8, and
surrounded by the springs a pressing the shoes against the platform t of the
support D (Figure 8). To preserve the rods from breaking or being damaged
when the apparatus is moved, etc., a turning bar u² (Figures 1, 8, and 13) is applied
to the lower end of the wooden board E, keeping if desired the shoes 1, 1, inside of
the board E (Figures 3,
and 7).
11
Instead of the shoes 7, l, a friction weight may be placed at the hind part of
the board E, as shown in Figure 10. The rod of this weight is moving in the
the same manner as in the foregoing case, viz., in the guiding eyes s¹. The weight
is also pressed, like the shoes l, against the platform t by the spring u¹.
The application of the shoes, and that of the friction weight, comparatively
secures a stable vertical position of the manometer apparatus, even when the
position of the support D is more or less inclined. Combined with the plummet
these contrivances permit of bringing the manometer easily and speedily in a
vertical position, or in case the axes of the manometer and plummet tubes not being
parallel, in a position of a constant incline.
Figure 9 represents the liquid reservoir A either of metal or glass. In the latter
case it must be placed in a metallic case with a vertical aperture to observe the
level of the liquid.
'
When the reservoir is made of metal, as shown in the Drawing, a float v may be
placed in it, from which through a hole in the lid of the reservoir passes the rod w

page_text: with a scale division permitting to judge of the level of liquid in the reservoir A, or
this reservoir may be provided with a water gauge. The lower part of the
reservoir A is provided with the pipe x and tap x¹, whereon is fixed one end of the
flexible tube C, and in the lid of the reservoir is an aperture y for air.. For ordinary
purposes the capacity of the reservoir is about one litre.
The flexible tube C may be of common india-rubber, with linen lining of
about 2 to 3 millimeters in diameter, at a length of 100 meters; such hose.
weighs about 3 kilograms.
2
The manometer B is filled with mercury to about one half the remaining part of
the cup b, the canals of the tubes c and C; and the greater part of the reservoir A
are filled with the acting liquid, i.,e., water. The filling of the apparatus with the
acting liquid is very easily done. For this purpose it is only required to place the
filled reservoir A above the manometer B and open the tap d, the water will
gradually drive the air out and fill the canals. The tap d must be shut sometime after
water is seen coming out.
The measuring of height by the manometrical altimeter is done as follows:-Let
us imagine we want to acertain the vertical distance between two points O and O¹
in any locality whatever, the distance between these points by far exceeding the
length of the india-rubber tube; further, let us admit the levelling to be proceeding
from O towards 01, and let us imagine along the distance between 0 and O¹ a certain
number of points 1, 2, 3, 4, 5, etc., distributed in such manner that the distance
between two points following each other be not greater than the length of the
india-rubber tube of the apparatus. First of all the liquid reservoir placed at
the point O, and the support with the manometer taken to the point 1. The mano-
meter being brought into a vertical position we note its indication. Let us presume
that this indication will be expressed by a; this done, the support with the mano-
meter is left at the point 1, the liquid reservoir placed at point 2, and the indication
of the manometer noted again, say, it indicates a, then the difference between the
indications a ad expresses the respective height of the points O and 2; further,
leaving the liquid reservoir at 2, the support with the manometer is removed to the
point 3, whereby we get for instance the indication a. Removing hereafter the
liquid reservoir to 4, and leaving the support with the manometer at 3, we obtain
the manometer indication as the difference of these two indications a
abg= = d₁
is the expression of the difference of height between the points 2 and 4. The
algebraic sum of the two differences d + d₁ however shows the respective height of
the points 4 and O.
-
-
Proceeding in the same manner we at last reach the point 01, obtaining a series of
differences d'd₁ d₂. d, the algebraic sum whereof determines the relative
elevation H of the point O above the point O¹, i.,e., H = (d + d + d₂ + .....
+ d₂) k..
The quantity represents the relation of the indications of the manometer to
the vertical motion of the liquid reservoir. This quantity changes when a change
of temperature takes place, which as is well known acts upon the density of liquids.
Therefore it is useful to verify from time to time coefficient k. For this purpose
the stay g of the support D is provided with a second hook (Figure 8) holding
the chain z of a determined length. Suspending the liquid reservoir A successively
first by the hook i¹, and then by the hook z' at the lower end of the chain z, and
noting the corresponding changes in the indications of the manometer we obtain
the ratio being the expression of the quantity k. For suspending the reservoir A
by the hooks and ¹ it is provided with the handle x² (Figure 9). Instead of the
chain z two small horizontal platforms may be fixed for the same purpose to one of
the boards E, E¹, (at the upper and lower end) at a determined distance from each
other, and the reservoir placed alternately on the one and the other of these platforms.
A separate stay provided with hooks for suspending, or platforms for placing the
reservoir A may be used likewise. In the latter case the verification of the mano-
meter indications may be performed at any distance from the same within reach of
the flexible hose C.
h

page_text: It is easily understood that such verification is only required when a change of
conditions is presumed, the verification itself may be made by the way while moving
the reservoir from place to place, and passing by the manometer.
The three legs 2 of the support D may be replaced by one stake c³ (Figure 10)
pointed at the lower end, by means of which the support is stuck into the ground, or
where the soil is rocky into a cruciform foot specially provided.
Expérience has taught that no matter whether the manometer is undergoing a
positive or negative pressure, i.,e., whether the reservoir with the liquid is placed
above or below the manometer, the sensitivity of the described manometrical altimeter
is sufficiently strong.
Working with the manometrical altimeter even with only one man for assistance,.
who only needs to know how to carry the liquid reservoir from place to place, and
at the same time take up the india-rubber tube is going on very speedily, and
with a mercury manometer one meter high, one may measure at a time up to
13 meters elevation which cannot be attained by employment of the ordinary
levelling instruments.
In measuring steep declivities, especially in case no particular accuracy be required
manometers of other systems may be employed as afore-mentioned, affording the
possibility of measuring up to 60 meters elevation at a time.
It is evident that the manometrical altimeter by its accuracy, small weight, and
simplicity of action, can with advantage replace the optic levelling instrument
generally used, especially in cases where the locality is hilly and covered with wood.
In the latter case this apparatus requires neither clearing of wood nor the selection
of visible points.
In architectural works the manometrical altimeter is useful for ascertaining the
regular laying of walls, foundations, floors, ceilings, for establishing staircases, for
ascertaining the settling of walls, etc. In all these cases the manometer can remain
in one place, and only the liquid reservoir wants moving; no matter whether the
india-rubber tube passes over walls, up or down, from one story to another, very
exact indications can always be obtained.
The manometrical altimeter may likewise be of great utility for the regulation
of water pipes, digging of canals and drains, building bridges, erection of machinery,
adjusting of shafts; in one word, wherever the determination of height is required.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Sydney Pitt in the Great Seal Patent Office on the 9th February
1878.
SYDNEY PITT, of Sutton, in the County of Surrey. "IMPROVEMENTS IN THE
METHOD OF MEASURING HEIGHTS BY MEANS OF A NEW APPARATUS." (A com-
munication from abroad by Nicholas Yagn and Lewis Survillo, both of Moscow,
Russia.)
The object of my Invention is the application of hydrostatic pressure to leveling,
and the construction of an apparatus called "manometrical altimeter," destined for
ascertaining the relative height of objects or of certain points in localities in cases
where direct measuring is difficult or even impossible.
Compared with the apparatus already in use for the same purpose my " imanome-
_trical altimeter" offers among others the advantage of considerably simplifying the
solution of problems in leveling, and of being adaptable even to such cases where
the other apparatus are found of no use.
The construction and action of the manometrical altimeter are based on the well-
known hydrostatic law, according to which the pressure produced by à column of.
liquid upon the sides of a vessel depends neither on the form nor the dimensions of
the vessel, but merely on the height of the column and the density of the liquid
itself.
Taking any reservoir A, and connecting the same by a flexible tube C with any
pressure gauge, as for instance, an open mercury monometer B, and the flexible tube
C, and reservoir A being filled with any liquid whatever, water for instance, the
indications of the manometer B will, according to the afore-mentioned law, only
show the relative height where the reservoir is placed. The diameter of the flexible
tube C, its length and shape, the nature of its sides, as well as the greater or lesser
height of placing the intermediate parts of the tube will have no influence whatever
upon the indications of the manometer. By this fact it becomes evident that when
the mercury manometer B is in a fixed and stable position its indications will only
change in case of the reservoir A with the liquid being moved in vertical
direction, and the changes will strictly correspond to the vertical motion of the
reservoir A. Admitting the reservoir A be placed at a certain height H, the indi-
cation of the manometer B will be = h. If we move the reservoir A to H¹ the
indication of the manometer will change from h to h + a, giving the following
|proportion:=H: H + H¹ = hha, hence H¹ =
x a. Here is a constant
h
H
H
quantity, and is fixed by experience, once for all, for every apparatus; consequently
for ascertaining the quantity H¹, we want only to. ascertain the quantity a. This
quantity is the difference between two consecutive indications of the manometer B,
which are obtained by simple counting on the scale of the manometer. On this
very combination are based the construction and action of my manometrical
altimeter.
The flexible tube C and reservoir A may be filled, instead of water, with alcohol
or any other convenient liquid.
The manometrical altimeter, the construction whereof is shown in-the Drawings
hereto annexed consists of three main parts, viz., the manometer, the reservoir, and
the flexible tube connecting the same.
As may be seen in the Drawings the manometer B itself consists of the bent glass
tube a, a, of which one end a is open, and the other a' being considerably shorter
is widened out in the shape of a small cup b, placed at about half the height of the
knee a.
The diameter of the cup b is made about four times as large as the inside of the
tube, and its capacity a little more than that of the whole canal of the tube.
The cup b may be of iron or of glass, with a metallic rim or lid on top, as shown
in Figure 1. From the lid of the cup b passes a crooked pipe c, at the upper bent

page_text: of which is the branch c¹ provided with the air tap d, and to the end of the pipe c
is fixed the free end of the flexible tube C, Figure 9.
For levelling not requiring particular accuracy may be employed a mercury
manometer without the cup b, but in order to diminish the chances for errors it is
required in such case to determine the position of mercury in both knees, while in
using the manometer with the cup it is determined only in the knee a.
The boards E, E¹, placed together conveniently, and fixed to each other by screws,
or some other way, form a case to the manometer, which is placed in the metallic
comb-like scale e, Figures 4 and 5.
The scale e can be moved up and down by means of the micrometrical screw e¹.
For this purpose, after placing the wooden case with the manometer there is fixed
on the top part of the scale e, by means of the screws e and e³, the cross piece e², with
a nut screw, Figures 5, 11, and 12, through which passes the screw e', turning in a
fixed frame e³, incased in the corresponding cavity e¹ of the board E¹, Figure 2. The
screw e when turning presses against the metallic plate e, which is kept in its place
by the screws c¹0 and e¹¹, Figures 11 and 12.
The pitch of the screw e¹ is equal to one millimetre. The circumference of the
head es of the screws is divided into fifty equal parts, and resting on the fixed disce
provided with a vernier or nonius.
The motion of the scale e is guided by the pegs f, which are fixed to the boards.
E, E, and pass through corresponding spaces of the scale e, Figures 6 and 7.
The three guiding pegs f may be reduced to two (upper and lower), or even one
below, since the screw e¹ itself, passing through the cross piece e², may serve as guide
above. Besides, it is evident that the fixed disc e, with the vernier and the microme-
trical screw e¹, duly fixed to the moving scale e with its frame and constant scale,
can be placed on the top of the apparatus, or in any other convenient place, as for
instance, near the bottom. The moving scale e may also, without departing from
my Invention, be made in the form of a case surrounding the boards E, E¹, on all
sides, the cuttings 1, 2, 3, etc., being wide enough to cover the clefts a² and a³. By
this construction the motion of the comb-like scale e, and consequently the indica-
tions of the manometer B can be exactly noted up to 6 millimeter.
For observing the level of mercury in the knees of the tube a, a¹, there are clefts
or rifts a², a³, cut through both wooden boards E, E, Figures 2 and 14, about three
millimeters wide, the first of which is about as long as the whole length of the tube
a, and the second equal to the size of the cup b at the end a¹.
It is evident that when a mercury monometer without the cup b is used the length
of the knee a¹ is made equal to the length of the knee a, and the length of the
cleft as equal to the length of the cleft a. These clefts are shut outside by the
comb-like scale e, so as to shine through the spaces of the comb, as shown in Figures 6
and 7. It is evident that looking through the spaces the light will pass only through
those parts of the clefts a², a³, that correspond with the parts of the tube a and cup b
not occupied by mercury.
The comb-like scale e is cut out in such manner as to place the upper edges of the
spaces at an exact distance of a certain number of centimeters from each other.
Besides, on one of the longitudinal ribs of the frame e³, Figures 6 and 12, of the
micrometrical screw e¹, divisions of one millimeter are marked at a length a little
more than the distance between two contiguous spaces of the comb c.
Along these
divisions the prominence b', Figures 4 and 6, of the scale e moves in such manner
that the position of the scale e can always be exactly determined by means of the
line b² marked on this prominence. The spaces of the comb-like scale, for more
convenience, are numbered 1, 2, 3, 4. As it is not required for leveling, according
to my method, to know the absolute height of the mercury column, and merely
wanted to know the changing thereof, i.e., the difference between two succeeding
indications, it needs no particular accuracy in placing the comb relating to the
wooden boards of the apparatus, and only requires that the distance between the
upper edges of the spaces should be strictly invariable.
-The counting of the manometer's indications by means of the comb-like scale e, is

page_text: performed as follows:-Looking toward the light through the teeth of the comb, we
remark at once the light shining through the first space above the mercury in the
part a of the tube. Let us say it be the eleventh space from below. Raising the
scale e by means of the micrometrical screw e', and observing the tenth space, which
as yet lets no light pass, we remark the moment when the first ray of light is passing
through the same. At this moment the turning of the screw e' is stopped, because
the appearance of light proves that the upper edge of the space 10 is level with the
surface of the mercury in the knee a of the manometer B. Observing on the divisions
of the frame e³ the number of millimeters the scale e was raised, and on the vernier
the part of turn given to the head e³, the height of mercury in the knee a of the
tube is exactly ascertained. If for instance the distance between the upper edges
of the spaces is two centimeters, and the tenth space had to be raised three
millimeters, and, besides the screw head e wanted turning for 253 divisions, the
height of the mercury is 203263 millimeters, or 203-506 millimeters.
.
For leveling not wanting minute exactness, the indications of the manometer may
be counted by means of an ordinary scale provided with a vernier and other
requisites generally used. In this case, however, the manometer B is fastened to the
scale immovably.
The manometrical apparatus is suspended by the eye h, Figures 7 and 8, at the
hook of the stay g of the support D. Although the manometer thus suspended will
strive to take a vertical position, this position will not be strictly determined nor
sufficiently stable, because the slightest draught of air or contact will shake the
manometer. For removing this inconvenience, I propose the application of the
plummet, and the friction shoes 1. Figures 1, 3, and 8. The plummet k is
placed in the glass tube m.
The metallic bottom n of this tube has in the centre
a conic point o. The line of the plummet k is fastened in the centre of the metallic
lid p covering the tube m, of which about one half is filled with alcohol, transparent
oil, or some other convenient liquid. The plummet k being in the liquid, will settle
incomparably sooner than without the same. For observing the position
of the plummet k, the board E' is provided with the cleft a*. Sidewise the
plummet is perfectly visible. The tube m, with the plummet k, can of course be
fastened at any place that may be thought convenient outside of the case E, E'.
The friction shoes l, l, are fixed. to the ends of the rods r, r, and provided with a
somewhat convex basis. The rods pass through the guiding eyes 8, and are
surrounded by the springs u, pressing the shoes against the platform t of the
support D, Figure 8. To preserve the rods from breaking or being damaged
when the apparatus is moved, etc., a turning bar u², Figures 1, 8, and 13, is
applied to the lower end of the wooden board E, keeping, if desired, the shoes 1, 1,
inside of the board E, Figures 3, 6, and 7.
I'
Instead of the shoes 1, 7, a friction weight may be placed at the hind part of the
board E, as shewn in Figure 10. The rod of this weight moves in the same
manner as in the foregoing case, viz., in the guiding eyes 8. The weight l'is also
pressed, like the shoes 7, against the platform t by the spring u'.
The application of the shoes and that of the friction weight comparatively secures
a stable vertical position of the manometer apparatus even when the position of the
support D is more or less inclined. Combined with the plummet, these contrivances
permit of bringing the manometer easily and speedily into a vertical position, or in
case of the axes of the manometer and plumet tubes not being parallel, into a position
of a constant incline.
Figure 9 represents the liquid reservoir A, either of metal or glass. In the
latter case it must be placed in a metallic case with a vertical aperture, to
observe the level of the liquid.
When the reservoir is made of metal, as shown in the Drawing, there may be
placed in it a float v, from which through a hole in the lid of the reservoir
passes the rod w, with a scale division for ascertaining the level of liquid in the
reservoir A, or this reservoir may be provided with a water gauge.
The lower part
of the reservoir A is provided with the pipe x and tap x', whereon is fixed one end
:

page_text: of the flexible tube C, and in the lid of the reservoir is an aperature y for air. For
ordinary purposes, the capacity of the reservoir is about one liter.
The flexible tube C may be of common india-rubber, with linen lining of about
two and a half to three and a half millimeters in diameter. At a length of one
hundred meters such hose weighs about three kilograms.
The manometer B is filled with mercury to about one half. The remaining part
of the cup b, the canals of the tubes c and C, and the greater part of the reservoir A;
are filled with the acting liquid, e.g. water. The filling of the apparatus with the
acting liquid is very easily done. For this purpose it is only required to place the
filled reservoir A above the manometer B, and open the tap d. The water will
gradually drive the air out and fill the canals. The tap d must be shut some time
after the water is seen coming out.
The measuring of height by the manometrical altimeter is done as follows:-Let
us imagine we want to ascertain the vertical distance between two points o and o',
in any locality whatever, the distance between these points by far exceeding the
length of the india-rubber tube.; further, let us admit the leveling to be proceeding
from o towards o¹, and let us imagine along the distance between o and o', a certain
number of points 1, 2, 3, 4, 5, etc., distributed in such manner that the distance
between two points following each other be not greater than the length of the india-
rubber tube of the apparatus. First of all the liquid reservoir is placed at the point o,
and the support with the manometer taken to the point 1. The manometer being
brought into a vertical position we note its indication. Let us presume that this
indication will be expressed by a. This done, the support with the manometer is
left at point 1, the liquid reservoir placed at point 2, and the indication of the
manometer noted again, say it indicates a, then the difference between the
indications a a₁,-d, expresses the respective height of the points o and 2. Further,
leaving the liquid reservoir at 2, the support, with the manometer, is removed to
the point 3, whereby we get for instance, the indication a. Removing hereafter
the liquid reservoir to 4, and leaving the support with the manometer at 3, we
obtain the manometer indication as. The difference of these two indications, a₂ α=d₁,
is the expression of the difference of height between the points 2 and 4. The
algebraic sum of the two differences, d + d, however, shows the respective height of
the points 4 and o.
Proceeding in the same manner we at last reach the point o¹, obtaining a series of
differences d d₁ d₂
d, the algebraic sum whereof determines the relative
elevation H of the point o above the point o¹, i. e, H=(d+d₁ + d₂ + . +dn) k.
The quantity k represents the relation of the indications of the manometer to the
vertical motion of the liquid reservoir. This quantity changes when a change of
temperature takes place, which as is well known acts upon the density of liquids.
Therefore it is useful to verify from time to time the co-efficient k. For this purpose
the stay g of the support D is provided with a second hook i¹, Figure 8 holding the
chain of a determined length. Suspending the liquid reservoir A successively,
first by the hook i¹, and then by the hook z' at the lower end of the chain z, and
noting the corresponding changes in the indications of the manometer, we obtain
the ratio h¹ being the expression of the quantity k. For suspending the reservoir A
by the hooks ¹ and z¹ it is provided with the handle x2, Figure 9. Instead of the
chain z two small horizontal platforms may be fixed for the same purpose to one
of the boards E, E', (at the upper and lower ends), at a determined distance from
each other, and the reservoir placed alternately on the one and the other of these
platforms. A separate stay, provided with hooks for suspending or platforms for
placing the reservoir A may be used likewise. In the latter case the verification of
the manometer indications may be performed at any distance from the same within
reach of the flexible hose C.
h
It is easily understood that such verification is only required when a change of
conditions is presumed. The verification itself may be made, by the way, while
moving the reservoir from place to place and passing by the manometer.

page_text: The three legs e² of the support D may be replaced by one stake c³, Figure 10,
pointed at the lower end, by means of which the support is stuck into the ground,
or where the soil is rocky, into a cruciform foot specially provided.
Experience has taught that no matter whether the manometer is undergoing a
positive or negative pressure, i. e., whether the reservoir with the liquid is placed
above or below the manometer, the sensitivity of the described manometrical
altimeter is sufficiently strong.
Work with the manometrical altimeter, even with only one man for assistance,
who only needs to know how to carry the liquid reservoir from place to place and
at the same time take up the india-rubber tube, is carried on very speedily, and
with a mercury manometer one meter high one may measure at a time up to
thirteen meters elevation, which cannot be attained by employment of the ordinary
leveling instruments.
In measuring steep declivities, especially in case no particular accuracy be
required, manometers of other systems may be employed, as afore-mentioned,
affording the possibility of measuring up to sixty meters elevation at a time.
It is evident that the manometrical altimeter, by its accuracy, small weight,
and simplicity of action, can with advantage compensate the optic leveling
instrument generally used, especially in cases where the locality is hilly and
covered with wood." In the latter case this apparatus requires neither clearing
of wood nor the selection of visible points.
In architectural works the manometrical altimeter is useful for ascertaining the
regular laying of walls, foundations, floors, ceilings, for establishing staircases, for
ascertaining the settling of walls, &c. In all these cases the manometer can remain
in one place and only the liquid reservoir wants moving. No matter whether the
india-rubber tube passes over walls, up or down from one story to another, I always
obtain very exact indications.
The manometrical altimeter may likewise be of great utility for the regulation of
water pipes, digging of canals and drainings, building bridges, erection of machinery,
adjusting of shafts; in one word, wherever the determination of height is required.
I claim as my Invention,-
First. The combination of the manometer B and casing boards E, with the adjust-
able scale e provided with slits or cuttings, as set forth.
Second. The combination of the support D and its platform with the measuring
gauge B and the spring shoes 7, as specified.
Third. The combination of the manometer B and scale e with the micrometrical
screw e¹ and the casing or boards E.
Fourth. The combination of the manometer B with the plummet k, support D,
and chain 2, as and for the purpose set forth.
Fifth. The combination of the tube m containing liquid with the plummet k.
In witness whereof, I, the said Sydney Pitt, have hereunto set my hand
and seal, this Eighth day of February, in the year of our Lord One
thousand eight hundred and seventy-eight.
TTזותCT
DIA
SYDNEY PITT. (L.S.)