Year: 1886

page_text: 1, JEAN MILE DESSEN DIER, OT
do hereby declare the nature of this invention, to be as follows:-
This invention consists in an apparatus for showing the intensity or actinism of
light.
The photometer consists essentially of a regulator which allows of the continued
exposure to the light of a certain volume of a mixture of chlorine and hydrogen in
spite of the formation of hydrochloric acid.
To obtain the said mixture in the exact proportions I preferably decompose
hydrochloric acid by an electric current the necessary apparatus being arranged in
a dark chamber.
Two electro magnets are also arranged one to close the circuit and the other to
open the circuit of the electrolysis apparatus, when a current passes through either
magnet respectively-and therefore control the formation of the mixed gases. In the
circuit of the first electro magnet is a third electro magnet controlling a cock for the
admission of the gas to the photometer, and in the circuit of second electro magnet is
a fourth electro magnet serving to close the said cock. These four electro magnets are
actuated by a special battery.
The photometer proper consists essentially of a tube bent more or less into the
shape of a U but one arm of the tube is longer than the other in proportion as 3 to 2.
The longer arm is closed at the upper end by a stopper through which pass two small
tubes, one supplying the gas from the apparatus before described-the other having a
cock and communicating with species of aspirators or bellows with a spring for
creating a vacuum in the tube when desired. The two arms of the U are divided by
a cock and from the centre of the bend of the U tube rises a further tube parallel to
the arms of the U tube and also divided from the said tube by a cock. This tube
serves to introduce liquid into the U tube The apparatus is filled with the liquid,
until its level stands at the centre of the longest arm which is reckoned zero."
apparatus up to this level, is blackened so as to exclude light from the liquid.
The longer tube is enclosed in a casing the front of which is caused to slide without
The

page_text: friction in this sliding cover is a small perforation the lower side of which corre
sponds when the cover is in its lowest position, to "zero"-This cover is attached to
a cord, which passes over a disc or pulley, and the other end of which carries a float
which rests on the surface of the liquid in the smaller branch of the U tube-and is
weighted to balance the sliding cover-Half the circumference of the disc is equal to
the distance from the zero to the summit of the longer branch of the U tube, less one
centimeter. On working the aspirator the liquid in the longer branch of the U tube
rises and that in the shorter branch corresponding falls, allowing the float also to
descend and the sliding cover to rise up so that the orifice therein also immediately
precedes the surface of the liquid-Gas being now caused to enter the liquid falls and
the space in the longer arm of the U tubes is filled with the gas-On now exposing
the photometer to light, the light entering the orifice in the sliding cover or shutter
will cause the gases to unite--and thereby condense so that the liquid will rise in the
tube at a rate proportional to the actinism of the light. The shutter will consequently
move up and the disc revolve. On the front of the disc is situated a scale and
indicator showing the distance moved by the shutter-At the opposite ends of the
scale are arranged metallic contacts so that when the indicator is at its lowest position
it may cause a contact which sets in action the electromagnets for opening the cock
and setting in action the electrolysing apparatus, and when it is in its highest position
it may cause contact which sets in action the contrary magnets for closing the said
cock and stopping the electrolysis.
A drum may be combined with the indicator to register the travel of the latter and
so keep a record of the actinism of light during any time, in any convenient manner.
Dated this 10th day of November 1886
HERBERT & Co.,
67, Strand, W.C.,
Agents to Applicant.

page_text: I, JEAN EMILE DESSENDIER, of Roanne, in the Republic of France, Manufacturer,
do hereby declare the nature of my 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 consists in an apparatus for showing the intensity or actinism of
light.
The photometer consists essentially of a device in which a constant relative volume
of hydrogen and chlorine may be exposed to the action of light so that the said gases
may be caused to unite more or less quickly according the intensity of the actinism of
the light, forming thereby hydrochloric acid gas which is dissolved as it is formed by
means of a suitable liquid solvent thereby reducing the volume of gas in the receptacle
with a rapidity proportionate to the actinism of the light, there being suitable means
for indicating the said decrease of volume.
The accompanying drawings illustrate apparatus for performing the invention.
Fig. 1 is a vertical sectional elevation of the whole apparatus.
Fig. 2 is a detail view.
Fig. 3 is a recording device adapted to be operated by the photometer or
actinometer herein described for registering the moveinents of the latter.
The photometer consists of a U tube the longer branch F being in proportion to the
shorter branch E as about three to two-From between these two branches rises the
central tube K in communication with the lower bend H of the U tube through
cock m―The longer branch F is also divided from the other two branches E and K
by means of cock p. n is a cock for emptying the liquid from the photometer-The
longer arm F is closed above by a stopper through which pass two tubes i and j
the former being in connection with the gas forming apparatus, and the latter in
connection with an aspirator or bellows I operated by a spring q for emptying the gas
or air from the branch F when the cock in the tube j is opened-s is a cock in
connection with the bellows, communicating with pipe which may be continued
away from the apparatus into a solution of potash or lime for preventing the emission
of gases, since the same would be liable to destroy the apparatus by attacking the
metallic parts thereof. The tubes EK F are blackened or encased up to the level of
the line y, the same being the zero of the instrument the U tube being filled with
liquid to this level through the tube K; the longer branch F of the U tube is enclosed
in a casing L having a sliding cover t (Fig. 2) with a horizontal slit t¹ therein the
said slit being in such a position as to illumine the interior of the branch F just above
the level of the liquid therein. The cover t slides without friction and is connected
to a cord u passing over the disk or pulley M and connected to a float
counter-

page_text: «
"2
balancing the cover and supported by the liquid in the arm E of the U tube-The
disk M is preferably of such diameter that half the circumference of the disk is equal
to the distance from the zero to the summit of the longer branch of the U tube
less about one centimeter. The disk M is pivoted at m¹ as freely as possible from
friction and to the disk is secured the indicator y' radially arranged thereon-Behind
the disk is the dial P suitably divided upon its periphery and extending preferably
about a half of the circumference of the disk-The dial P is stationary and carries the
pins qq the purpose of which is hereinafter described.
Since the purity of the hydrogen and chlorine and the exact proportions of these
are essential, the gases are preferably derived by electrolysis or electrical decom-
position of hydrochloric acid-For this purpose the apparatus hereinafter described
may be used.
A is a bottle or jar closed with stopper c and having therein plates a a of porous
carbon or other suitable material the said plates being in connection with the poles of a
battery or source of electricity B by means of wires bb, there being in the circuit a
contact breaker operated as hereinafter described-The jar A contains the hydro-
chloric acid to be decomposed and it is placed in communication with a wash bottle C
of known construction, from which the pipe e passes to the cock f, in communication
with tube i before mentioned-The jars A and C and pipes de i etc. are protected
from light. B¹ is a battery or source of electricity in connection with two circuits
adapted to be closed respectively by the contact of the indicator y' with the pins q'q".
One circuit comprises the battery B₁ electro magnets h and g and pin q', the other
circuit comprises the electromagnets ¹g and pin q-The electro magnet is
adapted to close the circuit for the formation of gas mixture, the electro magnet h to
interrupt said circuit. The electromagnet g closes the cock f. the electromagnet g¹
opens said cock.
The liquid in A. may be hydrochloric acid with oth of common salt. The liquid
in may be a solution of sea salt.-That in the U tube, .water with salt and chlorine
dissolved therein.
The operation of the apparatus is as follows; The cock k is opened and the
aspirator i draws the air out of the longer branch F of the tube, the liquid
ascends therein and descends in E and the disk M is turned until the indicator y¹
arrives against the pin q" when the liquid will have risen to within a centimeter of the
summit of the longer branch of the U tube-By this means a. current is produced
between the battery B₁ electromagnets h¹ g¹ and pin q3 indicator y' and thence to the
battery. Contact at bis closed and cock f is opened-The cock p is also closed by
hand preventing the return of the liquid; Gas mixture is now formed and passes
through the wash bottle C pipe e, cock i over liquid in F ont through aspirator I-
When the liquids are saturated the mixture of gas becomes uniform and then the
cock p is opened and the liquid in F descends the space above the same being filled
with gas-The cock k is closed by hand. When the level of liquid reaches the zero
line xy. the indicator y' arrives in contact with the pin q' whereby a circuit is formed
comprising the battery B¹ electromagnets and g by the action of which the contact
at b is broken and gas mixture ceases to be made, and the cock f is closed.
The apparatus being now exposed to the light to be tested, the light will illuminate
always the same volume of gas mixture through the slit in the cover t, and the actinism
of the light will cause the gas mixture so illuminated to be combined more or less
quickly according to the strength of the light and the hydrochloric acid so formed
will be dissolved by the liquid in the tube the said liquid rising to replace the gas so
absorbed.
The rapidity, with which the liquid rises, that is to say, of the movement of the
indicator y¹ over the dial P will therefore be a measure of the actinism of the light.
I is a door and g" a red glass screen through which the tube F may be viewed if
desired.
To enable the movement of the finger y' to be registered during a given time, the
recording device illustrated in Fig. 3 and hereinafter described may be employed.
✗ is a drum revolving once, say, in twenty four hours, or in twelve hours. G is a

page_text: screw spindle journalled paralled to said drum and carrying fixed to it at one end the
drum about which a cord is wound passing over pulley T and terminating in
weight S. FE is an escapement of any desired construction the same being operated.
by momentary currents passing through the electromagnet R-The armature D' of
said magnet is pivoted to the standard D and to the anchor E of the escapement.
P is a spring tending to return said armature after attraction thereof by the
magnet Rc is a wheel having ten teeth five being electrical conductors and five
insulators, the pulley M is also provided with teeth gearing with wheel e.
H' is a
writing finger attached to the boss H on the spindle G-J is a rail guiding the
finger H-As the disk M turns, contacts are made by the teeth thereof with those of
the wheel c whereby momentary currents pass at intervals through the coils of the
electromagnet R so that the armature thereof is attracted and the escapement wheel
permitted to be moved by the weight S, the spindle G is thus revolved and the
finger H¹ raised making an inclined mark upon the drum X, the slope of which
indicates the actinism of the light.
When the liquid in the tube F rises nearly to the summit thereof, the indicator y¹
arrives against the pin " whereby the cock fis opened, and new gas mixture is
supplied to the tube F until the zero is again reached and the contact of the
indicator y with the pin q' causes the entrance of gas mixture to cease-The escape-
ment F E may be such that the return movement of the disk M is without effect
thereon the rising of the finger H¹ is therefore never substantially arrested since the
return of the disk M is comparatively fast with regard to the motion of the drum X.
Having now particularly described and ascertained the nature of my said invention,
and in what manner the same is to be performed, I declare that what I claim is :-
.
1. Producing a continuous movement proportional to the intensity of the light by
aid of a mixture of chlorine and hydrogen in equal volumes, by means of a regulator
maintaining a constant volume of the gaseous mixture exposed to the light.
2. The general arrangement described and shown in the annexed drawings for
attaining this purpose.
Dated this 10th I of Aw1007