THE MICROSCOPE. 
may be mentioned Messrs. Goring, Lister, Coddington, Quecket, 
Mandl, Dujardin, Le Baillif, Seguier, De la Rue, and numerous 
others. 
The eminent makers of the British and Continental capitals are 
well known. Good instruments of the low-priced sort are made 
by nearly all the opticians ; but those who have more especially 
devoted their labours to the microscope, are Messrs. Ross, Smith 
and Beck, Powell and Lealand, Pritchard, Yarley, and Pillisdier, 
in London; Messrs. Nachet, Charles Chevalier and George 
Oberhauser, of Paris; MM. Ploessel and Schieck, of Vienna; and 
M. Pistor, of Berlin. 
Without the intention of assigning any relative precedence to 
these artists, we shall now present a brief description of some of 
the instruments, according as they are severally mounted by 
them. 
chevalier’s universal microscope. 
77. The mounting of this instrument has always appeared to 
me to offer as many conveniences and advantages to the observer 
as can be combined in such an apparatus. 
A mahogany case A, fig. 37, p. 1, containing a drawer B, in which 
the instrument and its appendages are packed when out of use, 
serves as its support. A strong brass pillar, c c, is firmly screwed 
into the top of the case, and upon this pillar the entire instrument 
is supported. 
The pillar c c sometimes is made in two lengths, which are 
screwed one upon the other, by which means the height of the 
instrument may be varied at pleasure, either one or both lengths 
being used. 
An arm E c is attached by a joint at E to the summit of the 
pillar c c, so that it can be moved on the joint E with a hinge 
motion, and may thus be placed at any angle with the pillar c c. 
In the figure it is represented at right angles with c c. 
To the middle d of the arm Ec,a square brass bar D F o is 
attached at right angles to E c , so that when E c is at right angles 
to c c, the bar d f a is parallel to c c. In the face of the bar 
dfg # which is presented to c c, a rack is cut. 
Two square pieces p and M are fitted to the bar dfg, and are 
moved at pleasure upwards and downwards upon it by means of 
pinions, having milled heads o and n. 
To the square piece p is attached the stage z, upon which the 
object is placed, and maintained in its position by two springs, 
one of which is shown in the figure. This stage is provided with 
several adjustments, which have been already explained (31 
et seq .). It will be sufficient for the present to observe that it 
is capable of being moved upwards and downwards with the 
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