IMPROVEMENTS IN MICROSCOPE SLIDES to be as follows:
Year: 1884

page_text: I, BERNARD PIFFARD of Hill House Hemel-Hempstead in the County of Herts
Gentleman do hereby declare the nature of my invention for "IMPROVEMENTS IN
MICROSCOPE SLIDES to be as follows:-
"
Microscope slides for thin objects are usually made of a strip of glass of
convenient length breadth and thickness and of a disc of thin glass which is
fixed to the surface of the strip by means of Canada balsam or other suitable
cement.
Slides for thick objects are sometimes made with a recess hollowed out of the
strip which recess is covered by a disc of glass resting on the surface of the strip
and fixed as above described.
The slides above referred to and all other slides at present in use have a
projection above the surface of the strip and this projection is often the cause of
injury to the slide. First during the construction of the slide: for if this projection
is touched before the Canada balsam or cement is dry which occupies many hours
the object is moved from its position on the strip and the slide is spoiled. Secondly
after the slide is finished; for the projection is always liable to be knocked off.
By my invention these defects are remedied: I make a recess in the strip of any
desired depth and preferably of cylindrical form, and I employ a disc of just
sufficient thickness to come, when placed in the recess over the object flush with
the surface of the strip.
I make box slides in a similar way by dishing the bottom of the recess so as to
leave a chamber for a thick object. This box is closed by a disc fixed with its
surface flush with the surface of the strip as before described. In both cases the
slide has on both sides a plane or flat surface without projection.
The cement I prefer to employ is Canada balsam because its refractive index is
the same as that of glass.
Dated this 1 day of January 1884.
CARPMAEL & Co.,
Agents for the Applicant.

page_text: I, BERNARD PIFFARD of Hill House Hemel Hempstead in the County of Herts
Gentleman do hereby declare the nature of my invention for "IMPROVEMENTS IN
MICROSCOPE SLIDES" and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
Microscope slides for thin objects are usually made of a strip of glass of
convenient length breadth and thickness and of a disc of thin glass which is
fixed to the surface of the strip by means of Canada balsam or other suitable
cement.
Slides for thick objects are sometimes made with a recess hollowed out of the
strip which recess is covered by a disc of glass resting on the surface of the strip
and fixed as above described.
The slides above referred to and all other slides at present in use have a
projection above the surface of the strip and this projection is often the cause
of injury to the slide. First during the construction of the slide, for if this
projection is touched before the Canada balsam or cement is dry which occupies
many hours the object is moved from its position on the strip and the slide is
spoiled. Secondly, after the slide is finished; for the projection is always liable to
be knocked off.
By my invention these defects are remedied; I make a recess in the strip of any
desired depth and preferably of cylindrical form, and I employ a disc of just
sufficient thickness to come, when placed in the recess over the object flush with
the surface of the strip.
I make box slides in a similar way by dishing the bottom of the recess so as to
leave a chamber for a thick object. This box is closed by a disc fixed with its
surface flush with the surface of the strip as before described, In both cases the
slide has on both sides a plane or flat surface without projection.
The cement I prefer to employ is Canada balsam because the refractive index is
the same as that of glass.
In order that my Invention may be fully understood and readily carried into
effect I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figures 1 and 2 are sections to a greatly enlarged scale of parts of two slides
constructed according to my invention-Figure 1 shews a slide for thin objects
and Figure 2 shows a box slide for thick objects.
The
a is the strip of glass and bis the disc which forms the cover-c (Figure 2) is a
hollow formed by dishing the bottom of the recess in the strip a. The way in
which I prefer to secure the disc b to the strip a is simply by putting Canada
balsam between them. In the slide shown at Figure 1 a thin layer would be
spread over the bottom of the recess and the object would be bedded in the
balsam. In Figure 2 the hollow c would be filled with Canada balsam.
advantage of using Canada balsam is that its refractive index being about the
same as that of glass no care need be taken in grinding the surfaces of the glass,
It
all inequalities are filled up by the balsam and no unequal refraction results.
is however evident that the disc may be secured in many other ways and that the
surface of the recess may be ground smooth or may be polished if desired.
In both the slides shown in the Drawing the upper surface of the disc comes
exactly flush with the surface of the strip and this is the best form but some of
the advantages of my invention would remain if the upper surface of the disc
were below or even above the surface of the strip.

page_text: 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:-
The manufacture of microscope slides in which the cover is sunk into a recess.
in the strip forming the slide substantially as described.
Deted thin 10th day of Winho 1001
CARPMAEL & Co.,
Agents for the Applicant.