A New or Improved Thermo and Radioscope.
Year: 1890

page_text: Date of Application, 11th July, 1890
Complete Specification Left, 10th Apr., 1891-Accepted, 16th May, 1891
PROVISIONAL SPECIFICATION.
A New or Improved Thermo and Radioscope.
1, ALFRED ROSLING BENNETT of Duddingston Park, Portobello, in the County
of Mid-Lothian, Telegraph Engineer, do hereby declare the nature of this invention
to be as follows:-
Under the invention a vane similar to the vanes used in the instrument known as
Crooke's radiometer is pivotted or suspended within a screen made of paper, metal,
glass or other substance and having an opening in one side thereof. When a ray of
heat such as sunlight, or lamp-light, or the heat from a vessel containing hot
liquid, is made to pass into or across the opening in the screen, the vane will rotate,
the direction of rotation being determined by the form of the opening.
Instead of a vane, a light wheel, a cap, a sphere or their equivalent may be used.
Dated this Tenth day of July 1890.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.
COMPLETE SPECIFICATION.
A New or Improved Thermo and Radioscope.
I, ALFRED ROSLING BENNETT, of 26 Booth Street, Manchester, Telegraph
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 :-
According to this invention, I construct apparatus, in which, by the influence of
heat motion is imparted to vanes, wheels, caps spheres, spirals, cones or other
objects pivotted or suspended within jackets, or screens, or in some modifications of
the invention, in proximity to screens.
When the vanes or other movable objects are small, light, and delicately poised,
they are influenced and set in motion by extremely small increments of temperature,
such as may be brought about by exposing the apparatus to sunlight, or even to
daylight when the sun is obscured; by placing the hand in contact with or close to,
the apparatus, or even by the approach of a living body.
When the movable objects are larger or heavier, a top as well as a bottom
bearing may advantageously be provided, and the source of heat may be a lamp,
fire or furnace.
The shape, arrangement and size of the apparatus may be varied within very
wide limits, and it is not necessary to maintain any fixed proportion between the
measurements of the movable object and the screen which encloses it, although the
best results are obtained when the object nearly fills the screen, space sufficient for
free rotation only being left.
The following details and measurements are, therefore, given only for the
purpose of enabling a workman to make an efficient apparatus in accordance with
the invention, and not because they are necessary for its operation.
The invention may be given effect to by constructing a screen, five inches high
and three inches in diameter, of the form shown in plan and perspective in
Figure I, of metal glass, mica or any other appropriate substance. The walls of
the screen may be one-thirtysecond part of an inch in thickness. The screen may
be fixed on a wooden base. On one side the screen is open to the air, and it is also
open to the air at the top.

page_text: In Figure I, S is the body of the screen, A the opening in its side and B the
base.
In Figure II are shown several of the forms which may be given to the movable
object to be placed within the screen, but these forms may be indefinitely varied.
The movable object should be poised or mounted within the screen; so as to
rotate with as little friction as possible, and so that it may revolve freely without
touching the walls of the screen.
Then if heat from any source be suffered to fall on the screen the object will
rotate, the most prompt and strongest motion being produced when heat falls on
the object through the opening A (Fig. 1).
If required to be sensitive to small increments of heat, the movable object may
be made of paper or thin metal, but if the apparatus is to be used with high
temperatures it is not necessary that lightness should be specially studied in its
construction.
In Figure III is illustrated a completed instrument consisting of a screen S fixed
on a base B, and having mounted within it the movable object G, which, in this
case, is a sphere revolving on a spindle, having one bearing fixed in the base and a
second bearing supported by cross wires at the top of the screen. The opening in
the screen through which the heat falls is shown at A..
By constructing the screen of glass or other transparent substance, and by
employing movable objects of diversified colours or bearing patterns, designs,
pictures maps, or mottos, the invention may be utilized as an instructive toy, and
for advertising purposes.
The movable object may take the form of a ring or zone cut into various shapes,
such as, a railway train, racing horses, or a procession.
The speed of rotation being considerable the objects may be cut or marked so as
to exhibit an intelligible design or motto only when in motion.
As the speed of rotation in any given instrument depends on the heat to which
it is exposed, the invention may be utilised as a thermometer. To this end the
instrument should be fixed in a room free from draughts and so as not to be affected
by accidental movements of the air in its vicinity. The source of heat to be
measured should be placed on a straight line with the opening in the screen at an
invariable height above the base, and mounted on a graduated slide which will
permit of its distance from the movable object being varied without deviation to
the right or left. External disturbances being excluded, it will be found that the
speed of rotation will vary with the advance or retrocession of the source of heat,
being always the same for the same temperature.
An instrument having been calibrated by the aid of an ordinary thermometer can
thus afterwards be used to compare temperatures. When so used it is well in order
to exclude external disturbances, to include the apparatus together with the source
of heat, in a large screen open at the top, the position of this large screen being.
kept invariable in respect to the apparatus it surrounds. The necessary adjustments
can be made through suitable doors in the large screen.
Figure IV shows a plan of such an arrangement, S being the apparatus H, the
source of heat mounted on a block which is caused to travel along the graduated
scale G, by means of a screw D, and crank E, placed outside the large screen F.
The movable object may be made to indicate or register its revolutions by causing,
the spindle to actuate any suitable counter. By fitting a commutator or a
make-and-break contact to the spindle or to the movable object itself, and employing
in connection therewith a voltaic battery, or by causing the spindle to revolve a
coil or wire within a magnetic field, or a permanent magnet in proximity to a coil
of wire, the revolutions may be indicated or registered at a distance. By the same
means the instrument may be made to announce an increase of temperature by
ringing bells or working armatures of electro-magnets.
In this connection a light centrifugal governor may be fitted to the spindle
arranged so as to permit the electric current to pass only after a pre-determined
speed has been attained. The apparatus when provided with a counter and guarded

page_text: against external disturbances may be modified to serve as a register or meter of
electric currents when such currents are strong, enough to heat in their passage a
wire placed in or across the aperture in the screen (A. Figure 1). Such a wire,
may be either the main circuit or a branch thereof, and it may be bent or spiralled
so as to present a maximum surface to the air entering the said aperture.
Rotation of the movable object will only occur while the current is passing, and
its speed will depend on the heat developed in the wire which will be proportional
to the amount of current: Therefore, if the heat-value of a revolution be
ascertained by experiment, the counter will indicate the amount of electricity that
has passed through the wire.
When fitted with a counter the invention may be used as a sunshine recorder.
For this purpose the instrument should be mounted on a movable.base-plate driven
by a clock in such manner, that, being properly set in the morning, the opening A,
Fig. I, may be automatically kept exposed to the course of the sun during the day.
The shape of the screen may be varied greatly so long as one or more apertures
are provided through which air may enter the screen. For instance, the screen S,
shown in Fig. V answers well. The movable object G will rotate in the direction
indicated by the curved arrow when heat represented by the dotted arrows falls on
it from the direction H.
Reversing the position of the screen S, as in Fig. VI, also causes reversal of the
direction of rotation. Screens may contain several movable objects. Thus, in
Figure VII, a screen S, is shown containing two movable objects rotating in
different directions under the influence of heat from the source H.
Instead of two, three or more movable objects may be placed within or in front
of a screen, and these may be mounted at different levels between the bottom and
top of the screen.
The screen instead of being close to the movable objects, as in Figure VII, may
be set several inches behind them.
It is not absolutely necessary that the screen should be curved or bent to angles,
for a simple straight screen as S, S, in Figures VIII and IX will show the effects,
although not so well.
When a cylindrical screen is used an opening in its side is not absolutely
necessary. The screen may consist of a perfect cylinder; provided one or more
apertures are formed in the base so shaped as to cause the air entering through
them to assume a slanting upward, and preferably, also a spiral or circular, course.
Such an arrangement is shown in elevation and plan in Fig. X, where A is an
aperture in the base B, through which the air enters the perfect cylinder S through
a channel slanting upward through the base.
As the results described depend on the motion of heated air within the screens
the effects are intensified by making the screens very tall or by fixing a funnel or
vertical tube of any suitable material above a short screen in such manner that the
air which enters the screen below can escape only by ascending through the funnel
or tube.
Rotation of the movable object may be obtained by causing heat to impinge on
such a funnel or tube. The heat rarefies the air in the funnel or tube which
ascends, and the colder air entering the screen below imparts motion to the object.
Although the best results are obtained when the top of the instrument is open to
the air, and some forms of screens such as the form shown in Figures I and III,
will only operate when such an opening more or less perfect exists, it is not always
necessary.
For instance, the screens shown in Figures V, VI, VII, VIII and IX will
operate when covered on the top. The movable objects may even be mounted in a
box closed at the top and open to the air on one side only as in Figure XI.
Whenever screens are described and drawn as rectangular in this Specification,
they may be curved or consist of walls meeting at other than right angles, and
wherever described and drawn as curved they may be angular.

page_text: 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:
In combination with screens as set forth, poised or suspended objects to which
motion is imparted by the influence of heat acting on the air within or in proximity
to the screens.
Dated this the Ninth day of April 1891.
CRUIKSHANK & FAIRWEATHER,
62, St. Vincent Street, Glasgow, Agents.