IMPROVEMENTS IN STEREOSCOPES AND OTHER OPTICAL INSTRUMENTS, AND IN STANDS OR SUPPORTS FOR STEREOSCOPES
Year: 1858

page_text: PROVISIONAL SPECIFICATION left by Henry Swan at the Office of
the Commissioners of Patents, with his Petition, on the 20th November
1858.
I, HENRY SWAN, of No. 5, Bishopsgate Without, in the City of London,
do hereby declare the nature of the Invention for "IMPROVEMENTS IN
STEREOSCOPES AND OTHER OPTICAL INSTRUMENTS, AND IN STANDS OR SUPPORTS FOR
STEREOSCOPES," to be as follows:-
This Invention has for its object improvements in stereoscopes and other
optical instruments, and in stands or supports for stereoscopes. In con-
structing stereoscopes the standard which connects the stage of the instrument
with the frame in which the glasses are fixed is for the purpose of adjustment
divided transversely into two parts, and in one of these parts two projecting
wires or prongs are fixed, and these enter corresponding holes in the other
part. The holes are lined interiorly with cloth, so that sufficient friction may
be offered to the sliding of the prongs in the holes, to retain them in any
position in which they may be placed. When the instrument is in use it is
held by a button attached to the. lower part of the standard, and the adjust-
ment of the distance between the picture and the glasses is effected by placing
the end of the thumb in a recess formed in the upper portion of the standard,
and moving it up or down till the proper distance is found. The portions of
the standard may either be rigidly fixed to the stage and to the frame of the
glasses, or may, if preferred to render the instrument more portable, be

page_text: attached by hinges furnished with springs similar to the springs of a pocket
knife.
In arranging opera glasses, and other similar optical instruments, the holding
of the instrument and its adjustment may be facilitated by fixing a button to
the portion which carries the object glasses, and a ring to the portion in which
the eye pieces are fixed, the ring being for the purpose of receiving the end of
the thumb of the hand holding the instrument, so that by it the two parts
of the instrument may be moved towards or from each other in the manner
already described.
In arranging stereoscopes also, in place of employing an opaque division
between the two semi-lenses or glasses of the instrument, as has been usual
heretofore (where the semi-lenses or glasses have not been placed in immediate
contact), they are separated by a plate of transparent or translucent material,
the material employed by preference being ribbed glass.
In the ordinary box form of stereoscope, in place of the single reflector
usually employed a series of narrow reflectors are used, these reflectors being.
arranged in front of the opening somewhat in the manner of a Venetian blind,
and they are furnished with apparatus by means of which they may be all
brought to the required inclination at the same time, and in some cases these
reflectors are made with reflecting surfaces on each side (or they may even be
so formed as to present more than two reflecting surfaces), and the different
surfaces are colored to reflect light of different tints.
In arranging stands or supports for stereoscopes two (or other number
of) series of levers, parallel the one to the other, and arranged on what
is known as the "lazy-tongs principle," are employed; that is to say, each
series is composed of levers of equal length jointed together in pairs at their
centres, the levers of each pair being also jointed at their extremities to the
ends of the levers of other pairs, except in the case of the levers of the bottom
and top pairs, which are suitably connected with the base of the stand or
support, and with the stereoscope respectively. The height of the stand or
support is adjusted by altering the angle, which the levers of cach pair make
with one another.