IMPROVEMENTS IN THE METHOD OF ASCERTAINING THE RELATIVE LEVEL OR DIFFERENCE OF LEVEL BETWEEN TWO OR MORE GIVEN POINTS, AND IN THE APPARATUS EMPLOYED therein
Year: 1876

page_text: LETTERS PATENT to Henry Nicholas Ground, of Saltburn-by-the-Sea, in the
County of York, for the Invention of "IMPROVEMENTS IN THE METHOD OF
ASCERTAINING THE RELATIVE LEVEL OR DIFFERENCE OF LEVEL BETWEEN TWO
OR MORE GIVEN POINTS, AND IN THE APPARATUS EMPLOYED therein.”
Sealed the 13th April 1877, and dated the 16th October 1876.
PROVISIONAL SPECIFICATION left by the said Henry Nicholas Ground at
the Office of the Commissioners of Patents on the 16th October 1876.
HENRY NICHOLAS GROUND, of Saltburn-by-the-Sea, in the County of York.
"IMPROVEMENTS IN THE METHOD OF ASCERTAINING THE RELATIVE LEVEL OR
DIFFERENCE OF LEVEL BETWEEN TWO OR MORE GIVEN POINTS, AND IN THE APPARATUS
EMPLOYED THEREIN."
This Invention has for object an improved system or method of finding the
relative level of or the difference of level between two or more points by observing
or measuring the height at which the surface or surfaces of a body of water or
other fluid contained in a suitable tube or tubes or other vessel or vessels stands
above or below each of the said points, and then deducting or adding the one
measurement from or to the other.
To carry out my Invention I proceed as follows:-I take two standards or
uprights made of any suitable size and material, each of such standards or uprights
having a convenient scale marked thereon, and having respectively an ordinary
glass gauge tube or other suitable vessel attached to or embedded or inserted therein.
1 connect such two tubes or other vessels together by means of a flexible tube of
convenient length attached to their lower ends in any convenient manner, such
flexible tube being made of vulcanite, gutta percha, or any other suitable material,
and into such connecting tube and glass tubes I introduce such a quantity of water
or other fluid, say, as will when the two standards are placed together fill the
flexible tube, and reach about half way up the standards. I then place each one of
such standards directly over or under two given points, which points for the sake
of illustration I will call A and B, and ascertain the distance which the surface or
Die A31

page_text: surfaces of the water or other fluid stands immediately above or below each of these
points by means of the scales marked on each of the standards or uprights as before
described. Thus, for instance, say at point A this reads 5 feet and at point B
1 foot; the difference of level between each point would of course be 4 feet. The
surface or surfaces of the water being of necessity absolutely level.
If it be desired to ascertain the relative level of or difference of level between
more than two points, say A, B, C, D, as in the method pursued with instruments
now in use I first find the difference as before described between A and B, and then
between B and C, finding the relative level of A and C by addition or subtraction,
and again repeat the operation for the point D.
Another form of the instrument would be to have short glass tubes or other
suitable vessels fixed at the ends of a flexible tube to be moved up or down separate
standards until the surface of the water becomes visible in each, and then read off
in the same way as already described. This form with standards of a fixed con-
venient length would be advantageously employed more especially in the particular
process of levelling known as contouring or finding the level lines on an uneven
surface.
My improved system of ascertaining any relative level or difference of level may
be applied to instruments constructed in many other forms than those here described
or referred to without departing from the principle of my Invention, I therefore
wish it to be understood that I do not bind myself to any particulary form of
instrument.
The flexible tube may be made if desired of a convenient known length or with
distances marked thereon, so that in making sections no other measuring chain
would be required.
The advantages of my improved method over those hitherto in use are,-
1st. The instrument can be more simply and cheaply constructed than the
ordinary level and staff now in use.
2nd. No time being required to set the instrument levelling can be done much
more quickly than by the old methods, and a great saving of the time of the
operator and his assistants effected.
3rd. The results are absolutely correct, as water must under all circumstances
find its own level, the only possible chance of error is in the reading of the scale,
and as the operator instead of reading the scale through a telescope at a distance
of as much as 200 yards as in the old method stands close to it; this chance is
really nil.
4th. The instrument cannot like those in use get out of adjustment.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henry Nicholas Ground in the Great Seal Patent Office on the
13th April 1877.
HENRY NICHOLAS GROUND, of Saltburn-by-the-Sea, in the County of York.
"IMPROVEMENTS IN THE METHOD OF ASCERTAINING THE RELATIVE LEVEL OR
DIFFERENCE OF LEVEL BETWEEN TWO OR MORE GIVEN POINTS, AND IN THE APPARATUS
EMPLOYED THEREIN."
This Invention has for its object an improved system or method of finding the
relative level of or the difference of level between two or more points by observing
or measuring the height at which the surface or surfaces of a body of water or other
fluid contained in a suitable tube or tubes, or other vessel or vessels stands above or
below each of the said points, and then deducting or adding the one measurement
from or to the other.

page_text: To carry out my Invention I proceed as follows:-I take two standards or
uprights made of any suitable size and material, each of such standards or uprights
having a suitable scale conveniently marked thereon, and respectively furnished
with an ordinary glass gauge tube or other suitable vessel either attached to or
embedded or inserted therein. I connect such two tubes or other vessels together
by means of a flexible tube of appropriate length attached to their lower ends in
any convenient manner, such flexible tube being preferably made of vulcanised
india-rubber or of vulcanite, gutta percha, or any other suitable material, and into
such connecting tube and glass tubes I introduce such a quantity of water or other
fluid as will when the two standards are placed together fill the flexible tube and
reach about half way up the glass tubes in the standards. I then place each one of
such standards directly over or under two given points, which points for the sake
of illustration I will call A and B, and ascertain the distance which the surface or
surfaces of the water or other fluid stands immediately above or below each of these
points by means of the scales marked on each of the standards or uprights as before
described. Thus, for instance, say at point A this reads five feet, and at point B
one foot; the difference of level between each point would of course be four feet, the
surface or surfaces of the water being of necessity absolutely level.
If it be desired to ascertain the relative level of or difference of level between
more than two points, say A, B, C, D, as in the method pursued with instruments
now in use I first find the difference as before described between A and B, and then
between B and C, finding the relative level of A and C by addition or subtraction,
and again repeat the operation for the point D.
Another form of the instrument would be to have short glass tubes or other
suitable vessels fixed at the ends of a flexible tube to be moved up or down separate
standards until the surface of the water becomes visible in each, and then read off
in the same way as already described. This form with standards of a fixed con-
venient length could be advantageously employed, more especially in the particular
process of levelling known as contouring or finding the level lines on an uneven
surface.
My improved system of ascertaining any relative level or difference of level may also
be applied to instruments constructed in many other forms than those here described
or referred to without departing from the principle of my Invention. I therefore
wish it to be understood that I do not bind myself to any particular form of
instrument.
The flexible tube may be made if desired of a convenient known length or with
distances marked thereon, so that in making sections no other measuring chain
would be required.
The advantages of my improved method over those hitherto in use are,-
1st. The instrument can be more simply and cheaply constructed than the
ordinary level and staff now in use.
2nd. No time being required to set the instrument levelling can be done much
more quickly than by the old methods, and a great saving of the time of the operator
and his assistants effected.
3rd. The results are absolutely correct, as water must under all circumstances
find its own level, the only possible risk of error being in the reading of the scale,
and as the operator instead of reading the scale through a telescope at a distance
of as much as 200 yards as in the old method stands close to it, this risk is
really nil
4th. The instrument cannot like those in present use get out of adjustment.
Having now particularly described and ascertained the nature of my said Inven-
tion and the manner of carrying the same into effect, I would have it understood
that in so doing I do not confine myself to any particular form of instrument as the
same may be modified in various ways without departing from the principle of my
Invention, but what I claim is the improved method of ascertaining the relative level
of or difference of level between two or more given points in the manner and by the

page_text: improved apparatus herein-before described and set forth, or any mere modification
of such improved apparatus.
In witness whereof, I, the said Henry Nicholas Ground, have hereunto set
my hand and seal, this Ninth day of April, in the year of our Lord One
thousand eight hundred and seventy-seven.
H. N. GROUND. (L.S.)