116 



other eye— and they could not get the image thrown npon the 

 outer halves or the inner halves without getting confusion. 



Mr. Crouch said the mention of the subject called to his 

 mind the fact that, some years ago, Mr. Ahrens made a prism 

 for the binocular which could be shifted so as to give in one 

 position a perfectly stereoscopic effect, and in the other a 

 pseudoscopic effect. He explained the construction of the 

 prism by a diagram on the board. The result was so perfect 

 that he rather wondered it had not been more generally 

 adopted. 



Mr. Karop thought the principle was patented, and, there- 

 fore, opticians were unable to make microscopes on that 

 principle without paying royalties. 



Mr. Crouch said he believed there was a patent, but that did 

 not interfere with his making several microscopes on the 

 principle. He got the prisms from Mr. Ahrens, who raised no 

 questions as to his adoption of them. 



Mr. Karop said he was sure the Members of the Club would 

 regret to hear of the death of Mr. W. W. Reeves, which 

 occurred on the morning of the 18th inst. Mr. Reeves was one 

 of the original founders of the Club, and continued one of its 

 Members to the end of his life, always taking the greatest in- 

 terest in its affairs. Those Members who were in the habit of 

 attending the Excursions of the Club would remember that his 

 botanical knowledge was always at their service in the identi- 

 fication of plants found, and in this and other ways he would 

 be greatly missed. 



Announcements of Excursions, etc., for the ensuing month 

 were then made, and the meeting terminated with the usual 

 Conversazione, the following objects being exhibited : — 



Peunatula phosphorea Mr. F. W. Andrew. 



EucJilanis triqiieta ... ... ... Mr. W. Burton. 



Asplanchia priodonta (mounted) ... Mr. C. Rousselet. 



Mr. E. M. Nelson also exhibited a model of a binocular 

 microscope as invented by Cherubin d'Orleans, in 1677, and 

 giving perfect pseudoscopic effect. 



