AN IMPROVED INSTRUMENT OR AP- PARATUS FOR ASCERTAINING LEVELS
Year: 1834

page_text: 10 ALL
BROWNE, of Bridgewater, in the County of Somerset, Merchant, send greeting.
WHEREAS His present most Excellent Majesty King William the Fourth,
by His Royal Letters Patent under the Great Seal of Great Britain, bearing
date at Westminster, the Twenty-third day of December, in the fifth year of His
reign, did, for Himself, His heirs and successors, give and grant unto me, the
said John Browne, His especial license, full power, sole privilege and authority,
that I, the said John Browne, my executors, administrators, and assigns, or
such others as I, the said John Browne, my executors, administrators, or
assigns, should at any time agree with, and no others, from time to time and
at all times during the term of years therein expressed, should and lawfully
might make, use, exercise, and vend, within England, Wales, and the Town
of Berwick-upon-Tweed, my Invention of "AN IMPROVED INSTRUMENT OR AP-
PARATUS FOR ASCERTAINING LEVELS;" in which said Letters Patent is contained
a proviso that I, the said John Browne, shall cause a particular description of
the nature of my said Invention, and in what manner the same is to be per-
formed, to be inrolled in His said Majesty's High Court of Chancery within
six calendar months next and immediately after the date of the said in part
recited Letters Patent, as in and by the same, reference being thereunto had,
will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Browne, do hereby declare that the nature of my said Invention, and the
manner in which the same is to be performed, is particularly described and

page_text: ascertained in and by the following description thereof, reference being had to
the Drawings hereunto annexed, and to the figures and letters marked thereon
(that is to say):-
My improved instrument or apparatus is designed for levelling or ascer
taining the difference of altitude of certain points of land extending over an
undulating surface of country, or for mining or excavating for banking, drain-
ing, and other purposes. The instrument consists of a flexible water-tight
tube, of any convenient length, having tubular glass vessels at its extremities.
This flexible tube with its glass vessels is to be nearly filled with water or
other fluid, and as the fluid at the two ends of the tube (however much the
tube may be contorted or extended) will naturally find its common level, the
two surfaces of the fluid, when seen in the two glass vessels at the ends of the
tube, will indicate the true horizontal line or corresponding altitude at the
two stations. In order to determine the exact measure of the altitude or
depression of the surface of the earth, or of any point of elevation at one
station compared to another station, the glass vessels at the extremities of the
flexible tube are attached to graduated station rods or staff's intended to be
placed perpendicularly at the stations, upon which rods or staff's the ends of
the tubes, with the glass vessels, may be slidden up or down for the purposes
of adjustment. The ends of the tubes are furnished with stopcocks to prevent
the escape of water, and also to admit air when the instrument is in operation.
The graduated station rods or staffs, with the ends of the flexible tube attached
thereto, being placed perpendicularly at the stations or points of observations,
the glass vessel at the lower station must be slidden up its rod, and that of the
higher station slidden down its rod, until the surfaces of the fluid in the tube
are seen in both glass vessels indicing or bisecting the graduations in the rods
or staffs. The surfaces of the fluid in the glass vessels will thus exhibit the
true horizontal line or level, and their heights from the ground at the respective
stations indicated by the graduations on the station rods or shafts will then
shew by comparison the difference of altitude between the two points of
observation. The several Figures in the Drawings hereunto annexed will
explain the construction and mode of adapting this instrument to the purpose
of ascertaining levels.
Fig. 1 is a side elevation of the instrument as placed when in use, the staff's
or rods being held upright by the persons using the level. Fig. 2 is a side
elevation of one of the glass vessels at the end of the tube, shewing the
method of connecting them with the staffs or measuring rods, which is drawn
on a larger scale. Fig. 3 is a vertical section of the same. Fig. 4 is a top
view of one of the ends, and Fig. 5 is a transverse section taken through the

page_text: stopcock. Let A and B in Fig. 1 represent the two stations or places on the
surface of the ground, the difference of altitude of which it is desired to
ascertain. The graduated staff's or measuring rods being thus placed at the
stations, the stopcock of the glass vessel at the higher ground is first to be
opened for the admission of the air, the person at the lower station then slides
the glass vessel at the end of the tube up the staff, at the same time opening
the cock for the admission of air, when the circulation of the fluid being free to the
pressure of the atmosphere it finds its level, which is seen in the two glass vessels
bisecting or indicating on the graduated, staff's or measuring rods on the dotted
line C, D. a and are the two graduated staff's or measuring rods stationed
at A and B. c and d the two glass tubular vessels affixed to the ends of the
flexible tube i, i, which glass vessels c, d, are protected by metal casings e, f,
and furnished with stopcocks g, h, for the admission of air. The flexible tube
may be made of hempen or woollen cloth saturated with a solution of india
rubber or caoutchouc in the manner india-rubber tubes are usually made, but
it may be constructed of leather or other flexible material, or of metal, as will
be hercin-after described. The glass vessels at the ends of the tube are con-
nected to the cords or staffs by the following means:-The staffs a and b are
passed through the triangular pieces h, k, extending from the cases e and f of
the glass tubes. The lower of these pieces k, k, are furnished with tightening
screws at 1, 1, for the purpose of fixing the ends of the tube to the staff's when
the fluid has found its level, and the surfaces are seen in the glasses. In
Fig. 1 the dotted line C to D shews the level of the fluid in the ends of the
tube; the surface of that in the glass c at the station A indicates, or is oppo-
site to the graduation of thirteen inches and three tenths of an inch up the
rod or measuring staff a, and that in
graduation of six inches on the staff b.
seven inches and three tenths shew the
the two stations. Fig. 6 is a partial section of one end of the instrument,
shewing another mode of connecting the glass vessels with the ends of the
flexible tube. Fig. 7 is a plan view of an instrument, having three different.
staff's or rods and glass vessels connected to three flexible tubes, by which
means the comparative altitudes of three different stations can be seen at.one
time, and, if desired, a fourth tube with its staff and vessel might be added.
Figs. 8 and 9 are representations of one method of constructing this instru-
ment with different lengths of metal tubes connected together by hollow joints
to allow of the free passage of the fluid. Fig. 8 is a side elevation, and
Fig. 9 is a plan or horizontal view of the same, and as the same letters of
reference are marked upon the parts corresponding to those in the former
the glass & bisects or indices at the
The difference between these being
difference of altitude or level between

page_text: Figures, the foregoing description will serve to explain these Figures. i, i, i,
are the lengths of metal tubes which are connected together, and to the glass
vessels at the ends of the tube, by the hollow joints at m, m.
Figure 10 represents another modification of my improved level, in which
two fluids of different specific gravities are used to ascertain the difference of
altitude between the stations, the heavier fluid sustaining the lighter, and
indicating the rise of the surface of the lighter fluid contained in the glass
vessel at the upper end of the instrument by a comparative rise of the surface
of the heavier fluid contained in the lower glass vessel, the scale or measuring
rod against which the upper surface of the heavier fluid indices or bisects
being accurately graduated to suit the difference in the specific gravities of the
two fluids. For example, mercury may be used as the heavier fluid, and
water as the lighter, when, on the one end of the tube containing the water
being raised to the higher station, the column of the water pressing upon the
mercury will cause the surface of the mercury in the other end of the tube at
the lower station to rise in relation to the differences of their specific gravities.
Let A and B represent the two stations, the different altitudes of which it is
desired to ascertain. The long flexible tube a, a, a, a, being filled with the
lighter fluid (say water), is connected to the glass vessel b, in which the level
or surface of the water is seen, and the other end connected to the larger glass
vessel or reservoir of mercury c. The lower end of the vessel c communicates
with the open glass tube d, in which the surface of the mercury is seen rising
and falling against the graduated scale e as the altitude of the column of the
water in the tube b is increased or diminished. The graduated scale e, against
which the surface of the mercury in the tube d indices, must, as before stated,
be accurately graduated to correspond with the different specific gravities of
the two dissimilar fluids; for, as the end of the instrument at B is elevated,.
the mercury will indicate by its proportionate rise in the tube & the increased
elevation of the column of water in the ratio of their comparative specific
gravities. The tube d and reservoir c are connected to the stafff by the
pieces k, so as to slide up and down it; and the scale e should also be made to
slide on the staff f. The water tube b is also connected to the staff g, and
made capable of sliding. There are proper stopcocks h, h, which are closed to
prevent the escape of the water and mercury when the instrument is not in
use; and the upper end of the tube d must also be plugged or stopped with a
cock; but all of these cocks must be open when the level is in action, for the
purpose of allowing the pressure of the atmosphere to act upon the fluids.
When the instrument is about to be put into operation, the staff f, with its
mercury tube, must first be placed on the lower station A, when all the cocks

page_text: must be opened, and the water vessel & be brought near to the mercury tube d,
and raised or lowered upon its staff g, until the surface of the water in the
vessel b, and of the mercury in the reservoir c and tube d, are in a line of
coincidence, then the scale e must be slidden until the zero or 0¹ on the scale.
stands opposite those surfaces. When the scale is thus adjusted, the staff g,
with the water vessel, may be carried to the upper station B; and as the
column of water is raised, so will the surface of the mercury in the tube d be
raised also (but only in proportion to the difference of their specific gravities),
indicating on the proportionate scale e the number of feet and inches to which
the column of water has been elevated at the higher station, and consequence
the difference of altitude between the two stations, as shewn at Fig. 10, where
the surface of the mercury indicates a rise of 4 inches and a half, which is
equal to four feet altitude of the surface of the water in the tube b. This
operation may be reversed, the end of the instrument with the mercury being.
placed upon the higher station, and. the water tube at the lower station, when
the mercury will necessarily fall in the tube d, and its depression indicate the
difference of altitudes between the stations.. If it should be thought desirable.
there may be placed in the tube d a small float, bearing upon the surface of
the mercury, counterbalanced by a weight and cord passed over a small pulley,
like the float of an ordinary dial barometer, such cord turning the axis of a
pulley, which carries an index or hand to mark the rise and fall of the surface
of the water on a circular graduated dial instead of the scale e. I would here
remark that it will be evident to all practical men that the specific gravity of
the water and mercury; or other fluids, will vary under different temperatures,
and consequently the scale of specific gravities by which the altitude of the
different stations or places to be measured will not at all times be precisely
correct; but this little inaccuracy may be rectified by tables of the propor-
tionate specific gravities of the two fluids under different temperatures; the
temperature of the atmosphere being ascertained by a thermometer at the
time the instrument is used.
Having explained the nature and construction of my instruments or appa-
ratus for ascertaining levels, I would remark that they are applicable to the
purposes of ascertaining the comparative altitudes of different places or stations,
and for various other purposes, but particularly for ascertaining a level in
excavating land either for mining, for canals, or in the construction of rail-
roads, embankments, mill dams, and in the drainage of land, and also in ascer-
taining levels for buildings, and for other purposes; and that I desire it to be
understood, and I hereby declare, that I do not intend to confine myself to the
precise forms or methods of constructing my instruments for ascertaining

page_text: levels, as shewn in the Drawings, as they are intended to be varied to suit
different purposes; but I claim particularly the sole use, application, and
employment of flexible or jointed tubes, for the purpose of containing fluids of
the same gravities or of different gravities, as herein set forth and described,
for the purpose of ascertaining a level, or ascertaining the comparative or
difference of altitudes of different stations or places.
In witness whereof, I, the said John Browne, have hereunto set my hand
and seal, this Twentieth day of June, One thousand eight hundred and