Automatic Apparatus for Producing X Rays, and showing their Effect on a Prepared Plate or Screen.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Automatic Apparatus for Producing X Rays, and showing their
Effect on a Prepared Plate or Screen.
I, HERBERT JOHN DOWSING Electrical Engineer 24 Budge Row Cannon Street
London E.C. do hereby declare the nature of this invention to be as follows:-
My invention consists of an apparatus for automatically working Crooke's Tubes for
producing effects known as X rays and for showing their effect upon a chemically
prepared plate, or fluorescent screen.
The electricity required for working the Crooke's tube is obtained from a primary
or secondary battery or it may be obtained from a supply circuit. It is caused to
pass through the primary of an induction coil and the high tension current from the
secondary led off to the tube. I sometimes employ an influence machine to produce
the high tension current direct thus dispensing with an induction coil. The whole
of the apparatus is suitably insulated and enclosed, one portion having a fluorescent
screen being made light tight with the exception of a small opening just large enough
to see into the box.
A Crook's tube is placed in another part of the same or a separate box a short
distance behind the screen and so fixed that the rays produced can pass through the
intervening space in which an object is placed and fall upon the back of the
fluorescent screen throwing an image of the opaque portions of the object upon
it. The Crook's tube may be enclosed in a case made of wood or any other
material which is transparent on the screen side to the rays.
Combined with the X Ray apparatus I can use a coin freed contrivance whereby
the coin is caused to release the mechanism, or make an electrical contact allowing
the apparatus to work.
A timing device may also be attached in order to cut off the supply of current at
any predetermined period. A counter or numerical indicator can be attached to
indicate the number of times the apparatus has been used.
Wires, terminals and connections necessary to complete the apparatus are
employed.
Automatic Apparatus for Producing X Rays, and showing their
Effect on a Prepared Plate or Screen.
I, HERBERT JOHN DOWSING, of 24 Budge Row, in the City of London, Engineer
do hereby declare the nature of this invention, and in what manner the same is to be

page_text: performed, to be particularly described and ascertained in and by the following
statement:
My invention consists of an apparatus for automatically working what are known
as Crookes tubes for producing effects known as X rays, and for showing such effects
upon a chemically prepared plate or fluorescent screen. And in order that the said
invention may be fully understood I will now proceed to describe the same with the
aid of the accompanying Drawing, which is a diagrammatic sectional plan of an
apparatus constructed in accordance with the invention.
A is a box divided into three parts, B, C, D, by two partitions E, F. The part or
division B is blackened inside, and is provided at one end with eye holes G preferably
provided with eye shades H, and at the other end with a fluorescent screen E. The
part or division C is intended to receive the object to be exposed to the X rays. The
part or division D contains the Crookes tube I and is provided with a side F, opposite
to the screen E, made of wood or other material which is transparent to the X rays.
The entire apparatus must be made impervious to ordinary light except at the eye
holes G. J represents a coin-freed apparatus of any suitable construction into which
the electrical connections between the battery or other source of electricity and the
primary of the Rhumkorf coil are brought and arranged in such manner that when a
coin is dropped into the coin-freed apparatus J the said connections are put into
circuit with the source of electricity. The said coin-freed apparatus is also provided
with a clockwork or other suitable time measuring apparatus, which is liberated or
set going by the introduction of the aforesaid coin, and cuts off the supply of electric
current at the expiration of any predetermined time.
A counter or other numerical indicator may also be attached to the apparatus to
indicate the number of times the apparatus has been used.
The electricity required for working the Crookes tube may be obtained from a
primary or secondary battery, or from a supply circuit. It is caused to pass through
the primary of a Rhumkorf induction coil, and the high tension current from the
secondary of such coil is led off to the Crookes tube. I sometimes employ an
influence machine to produce the high tension current direct thus dispensing with
an induction coil.
The action of the apparatus is as follows:-
:-
Assuming that the object to be submitted to the X rays is placed in the division C
of the box A between the fluorescent screen E and the partition F, which is
transparent to the X rays, on introducing an appropriate coin into the coin-freed
apparatus J the electric circuit is completed and the X rays are produced in the
Crookes tube I and are reflected in the usual way so as to throw the shadow of the
object on to the fluorescent screen E, and on applying the eyes to the holes G such
shadow will be clearly seen on the screen. The introduction of the coin into the
apparatus J not only closes the electric circuit but also liberates the clockwork or
other time measuring device which is then set in motion by its spring, weight, or
other actuating means, and breaks the said electric circuit automatically at the
expiration of a predetermined period of time such as one or two minutes for example,
during which the effect of the X rays will remain visible on the screen E through
the eye holes G.
The coin-freed apparatus J may be provided with suitable devices for winding up
the clockwork or other time measuring device before the coin is inserted in order
to secure the full maximum period of action of the apparatus in return for each coin
inserted.
It will be obvious that instead of the electric circuit being closed directly by the
insertion of the coin into the apparatus J it may be closed by the time measuring
device after the same has been liberated by the coin, and then opened by the said
device at the end of a certain period of time as above explained.
When an influence machine is used in place of a Rhumkorf coil the action of the
coin-freed apparatus is, in the first place, to release mechanism by which the influence
machine can be operated by the person using the apparatus or otherwise, and

page_text: secondly to control the time during which such influence apparatus can be
operated.
Instead of a Rhumkorf coil a suitable transformer may be used where an alternating
current supply is available, in which case the secondary circuit with a suitable
condenser is connected directly with the Crookes tube, and the automatic coin-freed
apparatus is arranged to open and close the primary circuit which receives the
alternating supply.
The object or objects intended to be exposed to the X rays may be inserted
separately into the division C, or one or more objects may be placed on a disc or
other device mounted on an axis which can be rotated by the person using the
apparatus, so as to bring either of the objects at pleasure into the line of sight, or
the objects may be mounted on a slide which can be drawn out and pushed in by the
person using the apparatus, or they may be presented or held between the screen E
and the Crookes tube I in any other suitable way.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that what I
claim is:-
Automatic apparatus for producing X rays and showing their effects on a
fluorescent screen, constructed and operating, substantially as described.
Dated this 13th day of October 1897.
H. J. DOWSING,
Per W. H. Beck,
115 Cannon Street, London, E.C., Agent.