206 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Fig. 39. 
1739. Benjamin Martin’s Pocket Reflecting Microscope with a 
micrometer. The instrument was dioptric : the word “ reflecting ,y 
applies solely to the illuminating mirror. Pig. 39 shows that it was 
of an entirely novel design ; the focussing 
was performed by a push-tube at B ; for 
illumination the outer tube was cut away 
in front, and a mirror placed at the bottom ; 
there was also a wide aperture P Q cut 
through the opposite side of the outer tube 
for the purpose of allowing slides to be 
passed through. One of the novelties was 
a rough micrometer fitted in the focus of 
the eye-lens, with an attached dial for the 
purpose of registering tenths of a revolution 
of the screw. Subsequently the outer tube 
was prolonged, making what is now called 
a drum-foot, in which a mirror was placed ; 
afterwards it was mounted on three legs* 
after the manner of the Culpeper. 
1740. B. Martin’s Universal Micro- 
scope was of crude design, exhibiting a 
throw-back to the telescope mount. 
1740. Lieberkuhn’s Solar Microscope,, 
or, as we should now say, Projection Micro- 
scope. The apparatus, mounted on a ball- 
and-socket in a window, was originally 
pointed at the sun ;‘but Cuff (1743) greatly 
improved it by attaching an elementary form' 
of heliostat (see E, fig. 40). In 1746, Adams, 
adapted his Microscope stand in a very in- 
genious manner to his projection apparatus,, 
thus forming the earliest prototype of the 
projection and photographic instruments of 
the present day. 
1742. Fig. 41 shows a scroll form of 
mount on a circular wooden foot, a great 
improvement over the complete telescope 
mount ; but we see the last remnant of a 
partial telescope mount ; for the Microscope 
could be turned round on the pin C D 
laterally, so that it might be pointed to 
the sky or to a candle flame. This form 
of instrument, as made by Adams, had the 
scroll in sections for the sake of porta- 
bility, and, mounted on a square box foot, 
became very popular ; it was still sold by 
Jones in 1798. 
1743. Lindsay’s Microscope (fig. 42) is 
a simple Microscope with a mirror. It has four points of interest: 
first, its extreme portability; secondly, its excellent workmanship; 
thirdly, it is the first Microscope in which we meet with a mechanical 
