= 
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H. J. Clark on the Microscope. 47 
stimulate our instrument makers to go on from one range to another, 
until they have conquered the difficulties which prev iously baffled them ; 
and then apply themselves to find out some new tests, which shall offer a 
fresh difficulty to Ky overcome, But it is = the only, nor can | regard 
it as the chief work of the microscope, to resolve the markin 
Diatomacee, or tests of the like difficulty ; aaa although 1 should consider 
this as the highest object of ee to our makers, if the performances 
of such lenses with test-objects were an fair measure of their general 
utility, yet as I think that I have Hettitinatrated: that the very conditions — 
of their construction render them inferior in this respect for the purposes 
at th 
at the lowest 
Raigaseie: the approval of those, as Dr. Carpenter says, 
‘‘who have most successfully employed the pucreneare in phys- 
iological investigations,” I do not hesitate for a moment to de- 
clare, that nothing could be more pernicious fe the best interests 
of science than these remarks. It is unfortunate that such mis- 
taken views should be displayed on this subject, where so great 
confidence has been placed,—by one, too, whose elementary ~ 
works on physiology have raised the belief, among many, that 
he is perfectly pongery with those very tissues —_ ch require 
the nicest and m id microscopical investigatio 
The illastrations which I have given of the iia value of 
highly corrected lenses in the st = of minute structures, are 
er pe T think, to refute Spay views; but I would like to say 
words more in conclusion, especially in reference to the 
fei relations * — investigations to other de epart- 
ments of natural 
a“ the help of better microscopes, in a is iikely to take 
the lead in it 
glimpses, 
done, had we possessed one of these highly finished instruments, 
I can confidently assert, that it is a grave error to tell opticians 
they had better devote themselves more particularly to the im- 
a of the ordi instruments, and let their transcen- 
corrections of widely gaping sigh serve in the mean 
while as playthings for curious amateurs 
