AN IMPROVED INSTRUMENT FOR CONCENTRATING LIGHT, APPLICABLE TO DENTAL, SURGICAL AND OTHER OPERATIONS " PROVISIONAL SPECIFICATION.
Year: 1865

page_text: LETTERS PATENT to Charles Rahn, of 29, Brook Street, Grosvenor
Square, in the County of Middlesex, Dentist, for the Invention of "AN
IMPROVED INSTRUMENT FOR CONCENTRATING LIGHT, APPLICABLE TO DENTAL,
SURGICAL AND OTHER OPERATIONS
"
PROVISIONAL SPECIFICATION. left by the said Charles Rahn at the
Office of the Commissioners of Patents, with his Petition, on the 2nd
March 1865.
I, CHARLES RAHN, of 29, Brook Street, Grosvenor Square, in the County of
Middlesex, Dentist, do hereby declare the nature of the said Invention for
"AN IMPROVED INSTRUMENT FOR CONCENTRATING LIGHT, APPLICABLE TO DENTAL,
SURGICAL, AND OTHER OPERATIONS," to be as follows:-
My improved instrument is intended for concentrating and intensifying
direct light from a lamp, gas flame, or other source of artificial light for dental,
surgical, and other operations. The effect of this instrument is to direct an
intense light upon a given spot, and to limit the area of illumination. to that
spot.
My improved instrument is constructed as hereafter explained.. I employ
a combination of lenses, comprising a condensing lens and two double convex
lenses, the foci of which are arranged to accord with the distance required by
the operator from the patient.
I fit this combination of lenses into a cone with draw tubes, having a rack
and pinion adjustment carried by a plate made slide to slide in dovetails. This
plate is furnished with racks, pinions, and nurled screw nuts for adjustment, to
enable the plate carrying the cone and draw tubes to be raised or depressed at

page_text: pleasure upon a plate made to form a screen, and jointed to a foot or stand.
This plate is capable of adjustment by a tangent screw and nurled nut to
obtain any angle of elevation or depression that may be desired.
The light may be either disconnected or it may be fixed to the instrument
with any well-known means of adjustment.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Rahn in the Great Seal Patent Office on the 1st
September 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
RAHN, of 29, Brook Street, Grosvenor Square, in the County of Middlesex,
Dentist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Second day of March, in the year of our Lord One
thousand eight hundred and sixty-five, in the twenty-eighth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the
said Charles Rahn, Her special licence that I, the said Charles Rahn, my
executors, administrators, and assigns, or such others as I, the said Charles
Rahn, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use, exercise,
and vend within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "AN IMPROVED INSTRU-
MENT FOR CONCENTRATING LIGHT, APPLICABLE TO DENTAL, SURGICAL, AND OTHER
OPERATIONS," upon the condition (amongst others) that I, the said Charles
Rahn, my executors or administrators, by an instrument in writing under
my, or their, or one of their hands and seals, should particularly describe
and ascertain the nature of the said Invention, and in what manner the same
was to be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said Charles Rahn, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof, reference being had to the Drawing hereunto annexed, that
is to say:-
My improved instrument is intended for concentrating and intensifying
direct light from a lamp, gas flame, or other source of artificial light for dental,

page_text: surgical, and other operations. The effect of this instrument is to direct
an intense light upon a given spot, and to limit the area of illumination to
that spot.
My improved instrument is constructed as hereafter explained and shown
in the accompanying Drawing, which is a perspective view. I employ a com-
bination of lenses, comprising a condensing lens and two double convex lenses,
the foci of which are arranged to accord with the distance required by the
operator from the patient.
I fit this combination of lenses into a cone a with draw tubes b, having a
rack-and-pinion adjustment c carried by a plate d made to slide in dovetails.
This plate is furnished with racks e, e, pinions and milled head nuts f, f, for
adjustment to enable the plate d carrying the cone and draw tubes to be
raised and lowered at pleasure upon a plate 9 made to form a screen, and
jointed to a foot or stand h. This plate is capable of adjustment by a tangent
screw and milled head nut i, to obtain any angle of elevation or depression
that may be desired.
The light may be either disconnected or it may be fixed to the instrument
with any well-known means of adjustment.
In the Drawing I have shewn a gas burner connected to a vertical bar j by
an adjustable collar and nut k, up and down which the light may be moved as
required; the lower part of the bar is formed with a collar and screw nut,
enable the light to be secured at any
working on a horizontal bar 1, to
desired distance from the plate d.
And having now described the nature, of my said Invention, and in what
manner the same is to be performed, I declare that I claim the improved
instrument for concentrating light, applicable to dental, surgical, and other
operations, constructed substantially in manner herein-before described.
In witness whereof, I, the said Charles Rabn, have hereunto set my
hand and seal, this First day of September, One thousand eight
hundred and sixty-five.
CHAS. RAHN. (L.S.)