QUEKETT MICROSCOPICAL CLUB. 417 



The Hon. Secretary read a paper on " Binocular Microscopes," 

 communicated by Mr. E. M. Nelson, F.R.M.S. In recent years 

 several binoculars have been introduced, none of which, however, 

 can be called new. The first, the Greenough, by Zeiss (Journal 

 R.M.S., 1897, pp. 599, 600), was a twin microscope a form of 

 binocular invented by Pere Cherubin d'Orleans nearly three 

 hundred years ago. The second by F. E. Ives, in 1902 {Journal 

 R.M.S., 1903, p. 85) is very similar to one designed by Wenham 

 in 1866 as a counterblast to Powell's high-power binocular, in 

 which the whole beam is sent into each eye. The third, a modifi- 

 cation of the second, by Leitz {Journal R.M.S., 1914, p. 5), and 

 the fourth, by Beck, which is very similar to that of Ives. 



Mr. Nelson concluded his paper by some remarks on the 

 position of the two new binoculars. From what has been said, 

 it will be seen that they are a class by themselves. It would be 

 quite inaccurate to entertain the idea that these instruments are 

 a new kind of stereoscopic binocular constructed to enter into 

 competition with, and finally to supersede, existing binoculars of 

 the Wenham and Stephenson type, for they only possess the first 

 attribute stereoscopism in a limited manner. Their use is 

 confined to the employment of full Ramsden discs in each eye 

 that is, for work with non-stereoscopic images. When prolonged 

 work is undertaken with one of the new binoculars, great relief 

 and comfort to the eyes will be secured. 



Messrs. Beck, represented by Mr. C. Beck and Mr. Creese, 

 exhibited two of their new model high-power binoculars, one 

 giving an excellent image of Pleurosigma angulation with a 1/1 2th 

 oil-immersion, and on the other stand a lower power exhibited to 

 perfection, first, stereoscopic, and, second, pseudo-stereoscopic 

 vision obtained by altering the tube-length. Mr. Creese also 

 exhibited a Wenham binocular with a l/6th objective, giving a 

 perfectly evenly illuminated field at 300 diameters of a section of 

 the eye of the drone-fly. 



Messrs. Leitz's London representative, Mr. J. W. Ogilvy, 

 showed seven stands of their new model, with powers ranging 

 from 1/1 2th oil-immersion apochromat and 1,500 diameters to 

 1 in. and x 35. Two Leitz-Greenough models with low powers 

 were also exhibited. The preparations shown included Amphi- 

 pleura pellucida, Poclura scale, rock sections, and histological 

 preparations. 



