Microscopes at the American Exhibition. By J. G. Hunt. 23 
are supplied with the concentric adjustable stage, thus adopting 
Zentmayer’s idea, introduced sixteen years ago. It is to be 
regretted that Mr. Crouch allowed his name to be connected with 
the introduction of the adjustable rotating stage, for it is exclu- 
sively an American invention. 
The stands of Nachet are not elegant in design, neither is it the 
experience of workers here that they are conveniently adapted to 
all kinds of scientific work, nor do they continue in perfect con- 
dition after much use. I can remember the time when the 
American market was largely supplied with indifferent French 
microscopes, but, happily, that day is past. 
Hartnack’s instruments were not on exhibition, but previous 
experience has taught me they compare unfavourably with other 
reputed first-class instruments in workmanship and finish. After 
experience with American and English microscopes they are un- 
satisfactory in the extreme. Some German microscopists, and their 
imitators elsewhere, indulge the sickly sentimentality of lauding 
Hartnack’s instruments as though they only were competent to do 
best work. In every respect, when compared with American and 
English first-class work, they are inferior. Clever working instru- 
ments in a restricted way they are, but they are not the best. 
From Germany I have never seen first-class microscopical 
brasswork, and much of it has come under my notice. German 
microscopes are creations of deformity, and, speaking comparatively, 
are not instruments of precision at all. In the great struggle for 
the survival of the fittest, they will rapidly perish from sight, as 
rapidly as workers become instructed in such things. 
American microscopes were in the minority at our Exhibition, 
if we estimate numbers alone. Not so if we consider beauty of 
design, workmanship, and originality of construction. Among 
such work, claiming to be first-class, Zentmayer’s is pre-eminent. 
It has no superior anywhere. The stands he placed on exhibition 
were the best microscopical work there. In all his best stands the 
adjustable rotating concentric stage is used, and has been for 
sixteen years, long before any foreign maker conceived the idea. 
The “ American Centennial” stand, for the first time exhibited 
on that occasion, is worthy of special notice. It combines speci- 
alties of construction not found in any other instrument, and its 
mechanical finish is more perfect and displays superior workman- 
ship to all others in the Exhibition or elsewhere. It is the only 
microscope stand constructed on accurate scientific principles. All 
its optical and mechanical parts are built around one primary 
centre, which is the focal point of the instrument. When placed 
horizontally, in the position for drawing, the entire microscope 
revolves around a centre which lies perpendicularly under the 
optical focus. A graduated base gives facility for approximative 
