Improvements in Hydrostatic Levelling Instruments.
Year: 1889

page_text: COMPLETE SPECIFICATION.
Improvements in Hydrostatic Levelling Instruments.
I, CARL THEODOR STRAUS, of Riga, Russia Civil Engineer, do hereby declare the
nature of this invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :-
This invention refers to hydrostatic levelling instruments, by which the exact
differences in heights of surfaces between two points may be directly read.
The invention is based upon the fact that the fluid contained in two vessels
connected with each other by pipes into or from which there is no other flow or
outflow, stands always horizontal and at the same level in each vessel.
According to my invention two equal, straight, faultless glass tubes open at both
ends are fastened into or onto wooden rods provided with divisions after the manner
of a thermometer, and the lower ends of the tubes are connected together by a hose
or pipe of the desired length say from 20 to 50 metres. The instrument thus formed
is filled with water so that the level of the fluid reaches say to the middle of the tubes.
The rods are set up in a perpendicular direction, the one at one, and the other at the
other of the two points of the surface, the difference of the height of which is to be
measured. The latter operation is effected by reading the heights on the divisions
of the two rods and subtracting the values thus obtained the one from the other.
In the accompanying drawing, Figure 1 shews a general view of a levelling
instrument constructed according to my invention, whilst Figures 2 to 6 inclusive,
shew various details as hereafter described.
In Figure 1, A represents one, and A¹ the other of the two levelling rods, and
B, the hose pipe or tube which connects the lower ends with each other.
The rods are similar to each other, thus the rod A, Figure 1, on the left hand,
represents the front view, the rod A Figure 1 on the right, the back view. Each rod
has a straight glass tube a carried by a wood piece or latten b, in the front of which
there is a half-cylindrical longitudinal groove 6° Figure 2 which is a section on
line of Figure 2, the latter being a vertical section of the lower portion of the
instrument; both Figures 2 and 2* being drawn to an enlarged scale, and it will be
observed that the glass tube a in those figures rests in the groove b°.
The latten b is turned at the upper and lower ends to a half round form as shewn
in dotted lines in Figure 2 and in full lines at Figure 3 which is a horizontal section
on the line y y of Figure 3*, the latter figure being an elevation of the part of the
instrument as shown in section at Figure 2, and by the aid of suitably formed
blocks 63, the latten 6 is made round, so that the glass tube a at the ends of the latten b
is fully covered.
At the upper and lower ends there is pushed on to the glass tube a short piece
of India rubber hose c so that the expansion or contraction of the tube is allowed for
in one or the other direction without fear of breakage. Over each of the round
ends 6' 6 of the latten is a metal cap marked e and d respectively in Figures 2ª 3*, 4
and_4* which_latter shew elevation and sectional views of the upper part of the
instrument. The upper cap d Figure 4 at the upper end of the tube a is formed
with a carrier in which a cock dis inserted. The lower metal cap e, Figure 2*
terminates in a bent conduit e¹ the bore of which communicates with the lower end of
the tube a and the free end of which is screwed on to the end of the hose or tube B
by means of a suitable screw. At the end of the conduit e¹ in the prolongation of
the tube a, a blunt point is provided by which the levelling rod is set on the
ground.
Finally each levelling rod carries on its front side right and left of the glass tube a
two measuring scales g, gl Figures 2, 3, and 4, so that the various heights of the fluid
may be read off. For this purpose there is a float h, Figures 4 and 4*, which is placed
in the glass tube of each levelling rod.

page_text: In some cases I may arrange the levelling rods as shewn in Figures 5, 5*,
and 6ª, Figure 5 represents a front view of the lower part of a levelling rod, Figure 6
shews a side view of Figure 5, and Figures 5 and 6* are cross sections respectively
on the line vv of Figure 5, and w, w of Figure 6.
In this case the glass tube a is inserted with its lower end in a metal shell k and
with its upper end in a similar shell. These shells are provided with back flanges k¹
and front brackets and are fastened with their back flanges on the latten b. The
upper shell is provided with a cock and a funnel as in the former construction,
whereas on the lower shell the hose B is screwed in the axis of the tube a. Between
the two front brackets k of the shells & the latten 6 bears upon its face on the right
and on the left hand of the glass tube a a ledge 6 and 6 Figure 6ª, which protect the
glass tube and bear on their face the scales g and g². The latten 6 extends over the
lower end of the glass tube a Figures 5 and 6 and terminates in a point which is
covered with a metal shoe b*. In other particulars the arrangement of the apparatus
is similar to that described with reference to the previous figures.
When the apparatus is prepared for use the hose B Figure 1, is screwed on to the
ends of the bent conduits et and after opening both cocks at the upper ends of
the rods, water is poured into the tube a of one rod, for which purpose a funnel d³,
Figures 4 and 4, is provided on the upper end of cock d'. Water is continued to be
poured in until the hose is filled and the fluid stands in both tubes in the middle of
the measuring rods; then both floats are put into the tubes which may be done by
first unscrewing the cocks d. Upon the filling of the apparatus with water it is
advantageous at the commencement to hold the hose high and then gradually to let
it down so that the air may be completely driven out of the hose.
If a
regular levelling is to be made, the same preparatory operations as in
levelling with the telescope or ordinary instrument must be executed. The lines must
first be set out then measured and at say 20, 25 or 50 metres distance small stakes
must be driven in the earth and numbered.
In levelling, each rod is carried by a man who has to set the same upon the
centre of one of the driven pegs and to hold it as vertically as possible.
Each bearer is accompanied by a reader, who after the setting up of the rod opens
the cock in the upper end of the carrier, then after the float has come to a standstill
the second reader reads off the position of the float upon the scale and enters the
result in a note book. For very high or low positions of the float, the reading may
be effected with the aid of a small mirror, which can be inserted in the cover of the
note book and set upon the edge of the rod. For this purpose the numbers upon one
edge the scale g', Figure 4 are arranged so that the reflected indication can be read.
After the reading and notation the cocks of both levelling rods are again closed
and both parties go the next peg forwards, in doing which both readers can assist in
the carrying of the hose. When the hose is say 50 metres long it is recommended
that a boy should carry the middle of the hose. Each stretch is preferably levelled
twice. The separate simultaneous readings are then compared, and by subtraction of
the ascertained values, the difference in height between the measured points is
ascertained.
As the setting up of the rods, the producing of the water level, and the reading,
occupy a very short time the work can be carried quickly forwards, for example with
stakes at 20 metres distance, about 8 kilometres, with stakes 50 metres a distance of
say from 12 to 15 kilometres may be levelled per day.
After the conclusion of the levelling the water is to be poured out (in which care is
to be taken that the floats are not lost), the apparatus to be dried and the hose
cleaned from the earth clinging to it. In case of the breakage of a tube it can be
easily replaced without the accuracy of the apparatus suffering thereby.
It may be further remarked that the expansion of the water has no influence upon
the accuracy of the height measurements, because the level in each tube is increased
by a half of the expansion, so that the same difference in height will result from the
subtraction of the readings.
All loss in the body of the water occasioned by usage, leakage or adhesion to the

page_text: glass walls, moreover all bendings and doublings of the hose, as well as all inequalities
in the diameters of the glass tubes, of the hose and of the connecting parts only
cause an alteration in the height of the water level in both levelling rods, the
differences resulting therefrom are mutually compensated by the subtraction of
the readings.
The other faults that occur upon levelling are with a careful construction of the rods
unimportant, so that they may be left unregarded.
The advantages which the described apparatus possess over the instruments in
common use, are as follows:-
(1) Any person without technical knowledge or experience, can carry out the
desired levelling in the given direction.
(2) The levelling can be carried out with greater accuracy in a shorter time,
particularly in mountainous lands.
(3) No open sight-line is necessary, on which account the apparatus is especially
adapted for levellings in towns and in woods.
(4) The levelling rods are during use not so easily subjected to alterations, that
occasion important errors, as is the case with the telescope and spirit level, which are
easily affected by the influence of heat. With the telescope moreover the tension of
the hair is altered by the moisture of the atmosphere.
(5) The cost of the complete apparatus is small.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In hydrostatic levelling instruments composed of two tubes a connected with
each other at their lower ends by a hose or flexible tube B; the arrangement of each
of the said tubes a in the groove 6° of a latten b the latter being provided with two
measuring scales g, g¹ the said tubes being almost entirely covered and therefore
protected; in combination with the fastening of each tube a on the latten 6 by means
of pieces of short flexible hose c and caps d and e, the upper cap d having a
carrier d in which a cock d is inserted and the lower cap e terminating in a bent
conduit e¹ and a blunt point e, all substantially as and for the purposes described with
reference to Figures 1 to 4* inclusive of the accompanying drawings.
2. The modified arrangement and fastening of each tube a on the graduated latten b
as shown in Figures 5, 5, 6 and 6* of the accompanying drawings.
Dated this Sixteenth day of April 1889.
Dated this Sixteenth day of April 1889.
C. T. STRAUS.
By Brewer & Son,
33, Chancery Lane, London, Patent Agents.