Tue MuicroscoricaL News 
AND 
NORTHERN MICROSCOPIST. 
No. 43. ILE, 1884. 
EXTRACTS FROM MRO oy EE) FRIPES 
TRANSLATION OF PROFESSOR ABBE'S: PAPER 
ON THE MICROSCOPE. 
Monthly Microscopical Journal, vol. xiv., page I9I. 
(Continued from page 145.) 
OW, to anyone who clearly realizes in his own mind what are 
the assumptions upon which a similitude between an object and 
its optical image is commonly accepted, the foregoing facts must 
suffice to lead to the conclusion that, under the circumstances 
above indicated, such acceptance is a purely arbitrary supposition. 
As a positive instance of the contrary stands the conclusion to 
which experiments lead by rigorous deduction, namely, that diferent 
structures always yteld the same microscopic images as soon as the 
difference of diffraction effect connected with them ts artificially 
removed from the action of the microscope ; and that similar structures 
as constantly yield different images when the diffractive effect taking 
place in the microscope is artificially rendered dissimilar. In other 
words, the images of structure arising from the operation of the 
diffractive process stand in no constant relation with the real con- 
stitution of the objects causing them, but rather with the diffraction 
phenomena themselves, which are the true causes of their formation. 
As this is not the place to enter into a physical exposition of such 
phenomena, it may suffice to say in brief, that the conclusions here 
deduced from facts won by direct observation, are fully substantiated 
by the theory of undulation of light, which shows not only why 
microscopic structural detail is not imaged according to dioptric 
law, but also how a different process of image formation is actually 
brought about. It can be shown that the images of the illumina- 
ting surface, which appear in the upper focal plane of the objective 
(the direct image and the diffraction images), must each represent, 
at the point of correspondence, equal oscillation phases when each 
single colour is examined separately. 
VOL. IV. 
