56 Description of an improved Microscope. [Jan. 
Ris a thing which —_ be made to attach to the stand at Q, 
and might hold a 30 inch telescope for the eye-pieces, of which 
the body, AB, and the astronomical eye-pieces, would serve 
very well, and thereby enable a person to have a telescope at a 
small additional expense. 
Having now, I think, thoroughly described this instrument 
so that the optician (for whose benefit this article is chiefly 
intended) may be enabled to make one without hesitation, I 
mor proceed to say a few words upon the nature and properties 
of it. 
{t will most probably be objected by the practical optician that 
this is an expensive, uncouth, top-heavy, gimcrack kind of a 
thing, and would not be near so saleable an article as the pretty 
toys and eye-traps that he is in the habit of making; that the 
old microscopes do very well; end that there is no occasion for 
putting himself out of his way with these new-fangled things. 
It is not always possible to combine utility and elegance. It 
is necessary for this instrument to be made on a large scale on 
account of the size of the great mirror, which is absolutely 
indispensable to furnish the quantity of light required for the 
solar apparatus, and to enable the instrument to act by lamp 
light as a lucernal microscope. The mirror is made oval, that 
it may throw down a round spectrum through the condensing 
glass ; and a plane mirror and lens are used instead of a concave 
mirror, for the same reason; otherwise the circle at the bottom 
of the camera will not be completely filled with light. This 
instrument was made by that acute and distinguished artist, Mr. 
Adie, of Edinburgh, inventor of the sympezometer. 
Now let us consider the manifold properties and the universal 
application of this instrument. 1. As a compound microscope 
for transparent objects; 2. As a compound microscope for. 
Opaque objects ; 3. As a compound solar microscope for trans- 
parent bodies; 4. As a compound solar for opaque bodies; 
5. As a lucernal microscope: for all these properties are com- 
bined together in this instrument, and (under correction from 
better judgement), I say, are in a very reformed and improved 
condition.—1. As a transparent microscope. Owing to the 
large quantity of light furnished by the large mirror, the apertures 
of the object glasses can afford to be made extremely small, 
which greatly improves the vision, as does the tube made to 
slide down over them. 2. As an opaque microscope, it performs 
in a most superior style, owing to the clearness of the vision and 
the abundance of light. The small mirror, which receives all the 
light from the great one, is likewise a better thing than the lens 
usually fixed on the stage to illumine the object, as it collects 
all the hght from the great mirror. As a transparent solar 
microscope, it has all the advantages which can be derived from 
using combined glasses instead of single lenses ; forjust such as 
® microscope is, such is the image produced by it. If it wants 
