JOURNAL 



OF THE 



ROYAL MICROSCOPICAL SOCIETY. 



FEBRUARY, 1914. 



TRANSACTIONS OF THE SOCIETY. 



I. — The Binocular Microscope. 

 By Felix Jentzsch, Ph.D. 



(Bead December 17, 1913.) 

 Figs. 1-3. 



1. The Employment of Binocular Microscopes 



in the Past. 



Ever since optical instruments were known, people have tried to 

 make them suitable for use with both eyes. There was no special 

 reason for this, nor had they any very clear idea of the require- 

 ments which such an instrument should fulfil, but one was quite 

 contented with the somewhat obvious experience of daily life, that 

 a man with both eyes intact is better than one who is blind on 

 one side. Thus, for instance, in the beginning of the seventeenth 

 century the Dutch spectacle-lens maker, Lippershey, was granted 

 a patent for a double telescope. This instrument was provided 

 with all sorts of improvements during the ensuing decades ; as, 

 for instance, an arrangement for placing the two objectives in a 

 convergent position. In 1677 Cherubin d'Orleans hit on the idea 

 of fitting up the Microscope as a binocular instrument. Whether 

 his arrangement was ever carried out or not we do not know. At 

 all events, and in spite of further experiments by Zahn in 1701, 

 the whole question was lost sight of, and we have to place on 

 record that for the next 150 years not the slightest interest was 

 taken in binocular Microscopes. 



It only came up again when C. H. Wheatstone developed his 

 epoch-making ideas on stereoscopic vision. This gave the lead 

 for an extended period in the development of binocular microscopy, 



Feb. 18th, mi 4 b 



