15-i J. RHEIXBERG ON THE COLLECTED PAPERS OF 



the other side of the Channel different views are still held on 

 various questions, and therefore, whether we endorse all the 

 views expressed or not, all will agree that it is valuable to have 

 a clear resume of them before us. I think you will consider me 

 justified in referring to this additional point of interest in the 

 paper, although I am aware that no supplementary reason is 

 needed to interest you in Dr. Ambronn's summary of the work 

 of the man to whom, more than any one else, we owe the per- 

 fection of the modern microscope. 



I would only acid that, if the phraseology of the translation 

 does not read quite so smoothly as it might, it is because I 

 thought it better to keep as literally to the German as possible, 

 rather than give a freer translation, in which the risk is always 

 run of the meaning being altered a little, according to the ideas 

 of the translator. 



Translation of Prof. H. Ambronn's Review, 



Amongst practical microscopists the many treatises of Abbe 

 on the theory of the microscope are little known, although their 

 contents form the best basis for a correct interpretation of 

 microscopic observations. For this strange fact several reasons 

 might be advanced : one of them certainly is that the individual 

 papers were issued in different journals, some of which are not 

 readily accessible to all. By the issue of the present collection, 

 prepared by some of the members of the scientific staff of the 

 Zeiss Optical Works, this cause has at any rate been eliminated, 

 especially as the almost entire absence of purely mathematical 

 deductions, and the clear, crisp form in which the chief results 

 are expressed, will materially facilitate their comprehension 

 by readers whose previous theoretical knowledge of the subject 

 may be limited. 



To be sure, Nageli and Schwendener had pointed out the 

 epoch-making work of Abbe, and subsequently Dippel did so at 

 much greater length in his Handbook on the Microscope, and it 

 was generally recognised that through Abbe's influence on the 

 construction of the microscope a powerful change had been 

 brought about. All the more, however, was one inclined to 

 consider as really existent what was observed by means of the 

 now so much improved microscope. That microscopic images 



