4 Beale_, on a Portable Field or Clinical Microscope, 
In examining objects by reflected light, sufficient illumina- 
tion is obtained from an ordinary wax candle placed at a 
short distance from the aperture, just above the object. But 
the most beautiful effects are obtained by using the Lieber- 
kuhn with direct light. 
The slide, as has been stated, is kept in contact with the 
lower part of the instrument, which I have called the stage, 
by a spring which is therefore made to press on the back of 
the slide. On the other side of the stage the little screw and 
clamp are placed so that the specimen may be fixed in any 
position that may be desired. 
In using this microscope the slide with the object to be 
examined is placed upon the stage, the thin glass being up- 
wards towards the object-glass, while the spring is made to 
press upon the under surface of the slide. The little screw 
is removed. The slide may now be moved in every position, 
and any particular object to be examined can readily be 
placed exactly under the object-glass. Tube a is withdrawn 
about two thirds of its length. The tube c being firmly held 
with the left-hand, b is grasped with the right, and with 
a screwing motion the object-glass is brought to its proper 
focus. The specimen having been fixed with the little clamp, 
and the bolt arranged at the right height, the instrument 
may be passed round a class. This microscope seems to be 
well suited to field-work and botanical purposes. It is not 
heavy, and, including the powers and an animalcule cage, 
will easily pack into a tube or case six and a half inches 
long and two inches in diameter. I constantly use it in 
clinical teaching. Urinary deposits, specimens of sputum, 
&c., may be examined by the patient^s bedside, and their 
characters demonstrated to the class. Lately, I have fitted 
the instrument to a little stand, on which a light has been 
placed in a suitable position, and the whole has been passed 
round in class, while the characters of the object shown were 
being described. When the arrangements are perfected, I 
believe this form of instrument will be found very valuable 
for demonstrating the microscopical characters of objects to 
a large number of persons assembled in classes. 
The instrument can be seen at Mr. Matthews', Portugal 
Street, Lincoln's Inn. 
