490 
BY A. LADY FRIEND. 
extensive Held of vision was obtained, but the optical power of the 
microscope remained the same, still, lenses of greater magnitude 
could thereby be used in the objectives. In Germany, in the last 
half of the eighteenth century, microscope makers distinguished 
themselves by developing and perfecting the compound micro¬ 
scope. We cannot, however, describe the improvements here. 
In 1772 Samuel Gottlieb Hoffmann, of Hanover, made micro¬ 
scopes which, according to Goeze, consisted of six objectives, by 
means of which twelve different results could be obtained, the 
strongest of which magnified three hundred and seventy diametres. 
Some years after Johann Heinrich Tiedemann constructed an ob¬ 
jective, whose focal distance was from 2-2 millimetre. The mic¬ 
roscope had a moveable table, worked by two screws. The ad¬ 
aptation was effected by means of a spring. Tiedemann’s micro¬ 
scope was considered by Bescke the best instrument at that time 
existing, and was very highly prized. The bottom of the box in 
which the microscope was kept was used as the base of the mic¬ 
roscope. In Germany, at the end of the past century and the be¬ 
ginning of the present, the following microscope makers are 
worthy of mention: Wagener, Elkner, Junker, and Wickert. 
The last two mentioned endeavored to make cheap microscopes 
without at the same time destroying their value and usefulness. 
Through these four gentlemen already mentioned the microscope 
was greatly improved. It is a fact worthy of mention that at this 
time as well as later in Nurnberg, in most manufactories the com¬ 
pound microscope was constructed of wood and pasteboard. In the 
beginning of this century the dioptric microscope, although greatly 
improved in its mechanism, was still in the most deplorable state 
of mediocrity. The simple microscope, with all its disadvantages, 
was used for scientific investigations. The compound microscope 
was looked upon simply as a plaything, and by Dilletanti it was 
so regarded. 
We have yet to mention still another kind of microscope, 
called the catadioptric instrument, which was intended to remedy 
the already mentioned defects of the compound dioptric micro¬ 
scope. We shall not, however, mention these instruments further, 
as they could not take the place of the dioptric microscope. The 
