The President's Address, 79 



specimens of an optician's skill in overcoming difficulties, 

 and they may be valuable for particular investigations ; but 

 tliey can never take the place of objectives in which the 

 angles of aperture are so proijortioned to focal length as to 

 make the microscopic vision of inanimate objects resemble 

 as closely as possible the natural vision of larger ones. Im- 

 portant observations on this subject have been made by Mr. 

 Wenham ; and Dr. Carpenter's paper on Nachet's binocular 

 contains some valuable information, reinforcing opinions he 

 has long expressed. 



It must not be supposed in these remarks that I am in any 

 way underrating Mr. Wray's labours. It is certainly de- 

 sirable that microscopists should be able to form their own 

 conclusions by experiments on this subject, and a well-made 

 two-thirds, such as Mr. Wray has presented to us, with what 

 may be described as an enormous aperture may be advan- 

 tageously compared with objectives of similar power made by 

 Mr. Wray or other makers, in which the angle of aperture is 

 much less. 



During the past year few important novelties in micro- 

 scopical apparatus appear to have been introduced. Mr. 

 Highley has brought out a very elegant miniature micro- 

 scope for the pocket. It is contained in a round German 

 silver case, four inches long and three quarters of an inch in 

 diameter, and can thus be easily carried in the pocket. 

 It is furnished with a tin box and a dividing objective, 

 and a draw tube. Its power is sufficient to enable the 

 collector to recognise the nature of his gatherings, when 

 they consist of Diatoms, Desmids, and other microscopic 

 Algse ; and in many cases it would afford the medical man 

 the means of distinguishing marked products. Though not 

 new in principle, the smallness and convenience of this little 

 instrument entitles it to mention. 



Messrs. Murray and Heath also exhibited a new form of 

 pocket microscope, which can either be used as a hand 

 microscope or secured by a single thumb-screw to a very 

 firm folding tripod stand. It is capable of being placed at 

 any desired inclination, and firmly fixed in any position by 

 the same scrcAV which fastens it to the stand, and which acts 

 as an axle clamp. The whole packs in a case measuring only 

 6Hn. X 3^ in. x 2lin. deep. 



Mr. Ross has devised a new object-holder, which will 

 prove of much use in many special inquiries. 



Microscopists frequently desire to examine unmounted ob- 

 jects of various dimensions, which cannot be held in the 

 stage forceps, partly on account of their limited oj^ening, 



