Apparatus for Measuring the Colour Intensity of Coloured Liquids and of Transparent Solid Matter.
Year: 1898

page_text: Complete Specification Left, 30th June, 1899-Accepted, 2nd Sept.,
1899
PROVISIONAL SPECIFICATION.
Apparatus for Measuring the Colour Intensity of Coloured Liquids
and of Transparent Solid Matter.
I, ARMAND CHARLES PHILIPPE LE DOCTE, Scientific Instrument Maker, of
Gembloux, Belgium, do hereby declare the nature of this invention to be as
follows:
This invention has for its object, to provide a reliable and convenient instru-
ment for measuring the intensity of colouration of coloured liquids and of
transparent solid matter, by comparing the colour intensity of the same with
the colour intensity of a standard liquid.
The instrument chiefly comprises two vertical tubes, one of which contains
the liquid to be compared, while the other contains the standard liquid and is
combined with a liquid reservoir adapted to vary the level of the liquid in the
said tube; a casing enclosing the said tubes and protecting them against acci-
dental illumination; an illuminating box or transmitter forming the base of the
said casing and adapted to transmit rays of light vertically through the lower
ends of the said tubes; and a receiving instrument mounted above the said
casing, said instrument containing a single eye-piece or set of ocular lenses and
a pair of total reflection prisms, so arranged that the rays transmitted through
the columns of liquid in the tubes are reflected by the prisms to the same eye-
piece, two opposite sides of one prism being silvered, while one side of the
other prism is silvered completely, and the other only partly (a part of the said
face being left free). The eye of the observer thus receives simultaneously the
rays which have passed through the two tubes.
The liquid reservoir connected with the standard tube may be mounted on a
carriage and raised or lowered along the upright frame of the apparatus by means
of a rack and pinion, while the reservoir remains in communication with the
standard tube through a flexible tube.
The casing which encloses the two vertical tubes is provided with two doors,
which may be opened simultaneously by means of a spring-actuated lever, for
giving access to the tube containing the standard liquid, and one of the said
doors carries a diaphanous screen, which, on the doors being opened, will be
placed in front of the tube, to facilitate the reading of the graduation.
The carriage supporting the liquid reservoir may be provided with a mirror
inclined at 45% and movable with the carriage, so that the operator may, by
means of the said mirror, observe the level of the standard liquid, whatever height
the liquid may occupy in the standard tube.
The said mirror may be used in conjunction with a second mirror, also inclined
at 45%, and mounted in the upper part of the apparatus in the axis of the lower
mirror, so that the operator may observe in a horizontal direction the graduation
of the tube containing the standard liquid, whatever height the liquid may
occupy in the said tube.
The top of the illuminating chamber or transmitter may have two openings

page_text: corresponding to the diameters of the vertical tubes, and underneath the said
openings a partition inclined at 45%, said partition carrying a sheet of unpolished
porcelain adapted to reflect upward the light received from an adjustable outer
mirror after it has passed through the transparent front wall or glass window
of the illuminating box.
T
Instead of a liquid reservoir mounted on a vertically movable carriage, I may
use two stationary reservoirs placed side by side close to the lower end of the
standard tube and at a lower level than the same, each reservoir communicating
through a separate stop-cock with a short tube leading to the lower end of the
standard tube: One of the said reservoirs contains the standard liquid, which
can be forced out of the reservoir into the standard tube by air pressure produced
by a flexible rubber bag or otherwise, and the other, serves to receive the liquid
flowing out of the standard tube. As an alternative to the above, I may use
two liquid reservoirs, one of which is placed at a higher level than the standard
tube, while the other is placed close to its lower end, each reservoir communica-
ting with the lower end of the standard tube through a separate stop cock, the
high level reservoir serving to supply the tube with standard liquid, while the
low level reservoir serves to receive the liquid which flows out of the said tube.
41
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411
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Dated this 29th day of September 1898.
...
Apparatus for: Measuring the Colour Intensity of Coloured. Liquids
and of Transparent Solid Matter.
I, ARMAND CHARLES PHILIPPE LE DOCTE, Scientific Instrument Maker, of
Gembloux, Belgium, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:
-
This invention has for its object, to provide a reliable and convenient instru-
ment for measuring the intensity of colouration of coloured liquids and of
transparent solid matter by comparing the colour intensity of the same with
that of a standard liquid.
This instrument chiefly comprises two tubes serving to contain the liquids to
be compared and protected from accidental illumination which might effect
their apparent colour intensity. One of these tubes contains the standard liquid
and is combined with a reservoir mounted on a vertically moveable carriage,
by means of which the level of the standard liquid in the measuring tube may
be varied with accuracy; the other tube contains the liquid to be compared.
The light which enters a special illuminating box passes through the two liquid
columns and is reflected horizontally into a single eye-piece by means of a special
optical combination serving to appreciate the colour intensities of the liquids
contained in the tubes.
The accompanying drawings show an example of an instrument embodying.my
invention,
Fig. 1 being a front elevation,
Fig. 2 a side elevation,
Fig. 3 a horizontal section along line 1-1 of Figs. 1 and 2, and
Fig. 4 a detail view.
Figs. 5 and 6 show two modifications of the apparatus represented by Figs. 1

page_text: Figs. 7 and 8, 9 and 10, respectively represent two modifications of detail.
The apparatus comprises a vertical stand H mounted on a pedestal I. To the
vertical stand H is secured a box K, the object of which will presently be stated
and which supports another box J. of rectangular shape and an opaque nature,
containing two glass tubes A and B, separated from end to end by a partition J'
(Fig. 3).
The glass tubes A and B are open at the top. The flat-bottomed tube A is
intended to receive the coloured solution to be tested and is marked with a
graduated scale consisting of five lines, situated, respectively, at 10, 20, 50, 100
and 200 millimetres from the bottom, and numbered 5, 10, 25, 50, 100. The
tube B is graduated in millimetres up to say the 200 millimetre level. This
tube, which is to receive the standard liquid, is provided at its lower end with a
nozzle or pipe joint C connected by an india-rubber tube D to a glass reservoir E
which is closed at the top by a similar nozzle or jet F fitted with a glass cock G.
The reservoir is carried by a clamp or holder U secured to a carriage R which
is adapted to slide in grooves extending from the top to the bottom of the
stand H, between racks S S; the vertical adjustment or motion of the carriage
is produced by turning the rod T fitted with pinions gearing into the racks and
controlled by the button or knob T¹.
The air-tight box K is closed at the top by a plate or diaphragm K¹ whereon
rests the tube-box J. This diaphragm has two perforations corresponding to
the tubes A and B respectively and equal to these tubes in diameter. In the
interior of the box K is a partition K inclined at an angle of 45° and supporting
a plate of unglazed porcelain or of polished opal glass; and the said box is more-
over provided with a translucent ground glass front wall K³ admitting a subdued
light from outside, which is reflected by a silvered mirror K* hinged at K5.and
capable of being inclined at any desired angle, so as to ensure the best possible
illumination.
The light received by the mirror K is reflected through the ground glass K³
on the the surface K, which in its turn reflects it vertically through the body of
liquid contained in the two tubes A and B.
Or the hinged mirror K might be dispensed with, and within the box K two
moveable reflectors K K might be substituted for the stationary reflector K²,
as shown in Figs. 9. and 10. In that case each of the two reflectors would be
controlled separately by a knob or button, such as K6 K7, so as to render the light
precisely equally intense in regard to both tubes A and B as the luminous rays
reach the eye. This arrangement may in some cases be preferable to that shown
in Fig. 2, inasmuch as where a single reflector such as K is used, the intensity
of the light illuminating the two tubes, as it reaches the eye, is not uniform,
owing to the possible differences in the transparency of the glasses, mirrors etc.;
through which the light has to pass.
The upper part of the box J is secured to a shelf or ledge L having two per-
forations for the tubes A and B to pass through. To this ledge is hinged a
box M having in its bottom part an aperture coinciding with the perforations
provided in the shelf L for the admission of the tubes. This box contains a
silvered mirror N inclined at an angle of 45° and thus adapted to reflect hori-
zontally the rays of light ascending vertically through the two tubes A and B.
These rays are reflected into an eve-piece or lunette P, by two total reflection
prisms 001 shown separately in Fig. 4.
These prisms consist each of a solid glass parallelopiped, and their two
reflecting surfaces 1 and 2 are inclined at an angle of 45° and silvered, such
silvered faces being arranged opposite each other.
The prism O is placed opposite the reflection of the tube B in the mirror N,
and its two sides 1 and 2 are silvered all over.
The prism 0 is placed inversely to the prism O and opposite the reflection of
the tube A in the glass N. The surface 2 of this prism is silvered all over, while
its surface is only partly silvered. The rays emitted from the tube B undergo

page_text: a double reflection in the said prism O and are projected on to the surface 1
of the prism O', through which they pass at its unsilvered part 02. The rays
proceeding from the tube A are likewise subjected to double reflection, that is,
to total reflection by the surface 2 of the prism 01, and to partial reflection by
the silvered portion only of the surface 1 of such prism.
It follows, that inspection of the surface 1 of the prism O¹ will show part of
the rays issuing from the tube B and also part of the rays issuing from the
tube A, as the lens-tube P is so situated as to collect all the rays falling on the
surface 1 of the prism O', the observer's eye, looking through the said lens-
tube P, simultaneously perceives the coloured rays proceeding from the two
tubes A and B.
The shape and arrangement of the silvered and unsilvered portions of the
surface 1 of the prism O¹ may vary, and the configuration of the surfaces inspected
will necessarily vary accordingly.
Were the unsilvered part of circular shape, for example, the two colourings
observed would take the shape of two concentric circles. Where, on the other
hand, the unsilvered part consists of straight tongues, the two colourings will
appear to the observer's view as so many tongues in juxtaposition; and so on.
These shapes may obviously be varied at the operator's will. And similarly
the outline of the image viewed through the lunette P may be either circular
or rectangular, according to the shape of the diaphragm 11 of the lunette 1',
forming an achromatic magnifying glass and terminating in an eye-piece Q.
Instead of this arrangement of prisms 0 0¹, the device exemplified by Figs. 7
and 8 might be adopted. It would consist of two mirrors, such as 0 0¹, inclined
at 45°, and serving as substitutes for the prisms shown in Fig. 4, each partly
reflecting the colouration by means of a third mirror N¹ on to which the lens-
tube P is directed. The outline of the field of each of the two colourations or
tinctures would be variable at will, as in the case illustrated by Fig. 4, in
accordance with the configuration of the silvered portion of the mirror 0. This
last mentioned arrangement affords the advantage, that it may be very readily
cleaned, while the shape of the field may be altered very quickly; and further,
it enables the observer's eye to be invariably directed upon a single surface, i.c.
with the rays always inclined at the same angle in regard to both whatever may
be the observer's position.
Upon the carriage or slide R, already referred to, a mirror V is inclined at
an angle of 45°. To the upper part of the stand is permanently secured a second
mirror V situated vertically above the mirror V and reflecting horizontally the
rays received from the latter.
Between the two mirrors V and V, an aperture V³ extends from the top to
the bottom of the stand H, exactly facing that part of the vertical box J which
contains the graduated tube B; the object of this aperture being to enable the
graduations of the tube B to be read off. To this end the portion of the box J
which contains the tube B is provided with two doors W W extending from
the upper to the lower end of the box J (Fig. 3). These two doors will open
wide when pressure is applied to a lever X connected by draw rods with each
of the doors respectively; and they close automatically, under the action of a
spring which tends to move the lever X back to its normal position, the moment
the said lever is freed from pressure.
To the door W. is secured a screen Y (Fig. 3), which whenever such door W
is opened, takes up its position opposite the tube B which is thus exposed; and
the scale-divisions of which become more readily visible in consequence. When
the said door is closed again, the screen turns down and resumes its position
against the wall of the box J.
The diameter of the reservoir E, which is movable along the stand H; is such,
that the level of the liquid it contains, which varies according to the position of
the slide R, is always approximately at the height of the mirror V. Hence it
follows that as the level of the liquid in the tube B is always identical with the

page_text: level of the liquid in the reservoir E¹, the surface of the liquid in the tube B
will in all cases be within the field of the mirror V, and be reflected by such
mirror on to the mirror V1 which, in its turn, will throw it back to the observer's
eye in the horizontal direction; owing to this arrangement, whatever may be
the height to which the liquid in the gauge-tube B rises, the eye receiving the
rays from the mirror V₁ will invariably perceive the surface of such liquid and
the corresponding mark of the graduated scale on the tube.
The apparatus is used in the following manner :-
The liquid to be tested is filled into the tube A, and the liquid employed as
a standard of comparison, into the tube B and the reservoir E.
The rays emitted by the illuminating box K pass through the two columns
of liquid, are reflected by the mirror N, and then pass through the prisms or
mirrors 0 0¹. The observer, whose eye is placed at Q, perceives a disc presenting
two different shades of colouring. In order to obtain a disc coloured with uniform
intensity, the knob of the rack is operated, whereby the slide R-and also,
consequently, the reservoir E and mirror V-are raised or lowered, until the
desired result is attained. All that is necessary, now, is to read off on the scale
of the gauge-tube B, the level reached by the standard liquid which this tube
contains. To this end, the observer takes his eye off the spy-hole Q and applies
it to the mirror V1; while at the same time, he depresses the lever X which opens
the doors W and W, thereby fully exposing the graduated gauge-tube and
bringing the diaphanous screen Y in front of such tube. The line of the gradua-
tion, corresponding to the level of the liquid, will then be reflected by the
mirror V and deflected by the mirror V₁, whence it may be directly read off.
After
Where several different, but similarly tinged liquids have to be observed
in succession, it suffices to previously fill each of them into the tube A.
examining the first tube, the box M, with the lens-tube P, is raised on its hinge;
the first tube A is removed from the box J; a fresh tube is inserted, and another
observation is proceeded with.
Where it is necessary to pass from one standard liquid to one or more other
standard liquids, it is sufficient to fill each of these into a graduated tube B
fitted with its reservoir E. Then, upon raising the box M, and while keeping
the doors W W open, the graduated tube B is removed, along with its reser-
voir E, and replaced by the tube and reservoir containing the standard liquid
to be employed next.
The box K is illuminated either by day-light or by artificial light of any
suitable kind arranged in the proper position.
In some cases it may be convenient, for the purpose of adjusting the shades
of colouring, to interpose a coloured compensating glass between the tubes A
and B and the observer's eye. To this end, there is provided under the prisms
or mirrors, a horizontal slide-way enabling a suitable glass-plate to be readily
placed in position or removed. This arrangement enables, not only the colour
intensity of the tinged glasses, moved up over the top of the tube A, to be
determined, but also the uniformity of coloration of the standard liquid to be
tested, by comparing it with a similarly coloured glass, no matter of what shade
or intensity, which has been retained as a standard of comparison.
In certain, altogether exceptional cases, where the standard liquid is apt to
affect injuriously the india rubber tube D, either of the two modified arrange-
ments shown in Figs. 5 and 6 may be employed.
In the modification represented in Fig. 5, the tube B is connected by two
glass tubes with two reservoirs or chambers a and b, closed at the top by means
of a cock and fitted with a jet.or nozzle c. Normally, the chamber b is empty,
while the other chamber a is filled with standard liquid for three-fourths of its
capacity. In order to cause the liquid to rise in the tube B the air in the
chamber a is compressed by means of an india rubber ball d provided with a
throttling device. Upon the top of the chamber a being opened, the pressure
causes the liquid to rise in the tube B. By opening the top of the chamber b

page_text: on the other hand, liquid is admitted into this chamber from the tube B. Thus,
by the operation of the two taps or cocks, the level of the liquid contained in
the tube B may be varied. When the chamber a is empty and the chamber b
full, air pressure is brought into operation in the last-mentioned chamber, while
the chamber a serves as a receiver or collector.
In the modification shewn in Fig. 6 the tube B is connected by properly luted
glass tubes, with two chambers a and b one of which a,, is above, and the other b
below the bottom of the tube B. These two chambers are separated from each
other by two taps. The chamber a contains the standard liquid; and when its
tap is opened, liquid flows from this chamber into the tube B while, when the
tap of the chamber is opened, such liquid enters the latter chamber, when the
chamber is full, and the chamber a empty, the two taps are opened: the orifice.
of the tube B is stopped, and, by injecting air into the chamber the liquid is.
forced from the chamber into the chamber a.
In the example hereinabove described observation takes place in the horizontal
direction, but it will be understood that the instrument might, if preferred, be
fitted for observation in the vertical direction. Besides, it is self-evident that-
in the latter case especially-the mirror V1 might be dispensed with, a single
mirror V, being used.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed we declare that what
we claim is :-
-
1. Apparatus for measuring the colour intensity of coloured liquids or trans-
parent solids, comprising in its construction two tubes one of which contains the
liquid to be compared, while the other contains a standard liquid and is connected
with a liquid reservoir adapted to vary the level of the liquid in the standard
tube, a box enclosing the said tubes and serving to protect them from accidental
illumination, an illuminating chamber situated below the said box and provided
with means for projecting rays of light through the said tubes, and an optical
receiving instrument adapted to receive the rays which have passed through the
said tubes and to deflect them into a single eye-piece by means of mirrors or
by means of two total reflection prisms, one of which has two silvered reflecting
surfaces opposite each other, while the other has a reflecting face, silvered all
over and a reflecting face silvered in part, substantially as described:
2. A colour measuring instrument or tintometer of the type specified, in which
the reservoir for the standard liquid mounted on a carriage is adjustable along
the stand of the instrument by means of a toothed rack and pinion, and connected.
by means of a flexible tube with the tubes intended to hold the standard liquid,
substantially as described.
3. A colour measuring instrument or tintometer of the type specified, in which
the box enclosing the measuring tubes has two doors adapted to be opened simul-
taneously by means of a spring lever, so as to expose the tube containing the
standard liquid, one of the said doors being provided with a diaphanous screen
adapted to place itself in front of the graduated tube on the doors being opened,
in order to facilitate the reading of the graduation, substantially as described.
4. A colour measuring instrument of the type specified, in which the carriage
supporting the liquid reservoir is provided with a mirror inclined at 45° and
adapted to show the height of the liquid in the standard tube, whatever the height
of the standard liquid in the said tubes may be, substantially as described.
5. A colour measuring instrument of the type specified, in which the moveable
carriage supports a mirror inclined at 45°, while a second mirror placed at the
upper part of the instrument is adapted to receive the rays reflected upward from
the moveable mirror and to deflect them in a horizontal direction, so as to render
the graduation of the standard tube visible, whatever height the standard liquid
may occupy in the same, substantially as described.
6. A colour measuring instrument of the type specified, in which the illumina-

page_text: ting chamber is formed by a box having in its top two apertures corresponding
to the diameter of the liquid tubes and a partition inclined at 45° and provided
with a porcelain plate adapted to deflect vertically upward the light which has
fallen on a mirror with adjustable inclination and thence passed through a front
wall of ground glass, substantially as described.
7. A colour measuring instrument of the type specified, in which the tube
serving. to hold the standard liquid is connected by means of tubes and stopcocks
with two receptacles placed below the said tubes, one of the receptacles con-
taining the said liquid and being combined with means for forcing the same
into the measuring tube, preferably by air pressure, while the other receptacle
serves as receiver for the liquid flowing out of the measuring tube, substantially
as described.
8. A colour measuring apparatus of the type specified, in which the tube
for the standard liquid is connected by tubes and stopcocks with two receptacles,
one of which is at a high level compared with the measuring tube, and the other
below the said tube, in order to serve as receiver for the liquid flowing out of
the measuring tube, substantially as described.
Dated this 30th day of June 1899
FAIRFAX & WETTER,
Agents, 37 and 39, Essex Street, Strand; London.