PHOTOGRAPHING MINUTE OBJECTS. 387 



this, most of the ordinary objects may be photographed, such as 

 parts of insects, sections of wood, and most of the larger diatoms. 



There are many different forms of photo-micrographic appara- 

 tus on the market now ; most of the opticians make one or other 

 form a stock article. Of some of the better instruments I will 

 show slides that I have made on purpose, then perhaps it will be 

 better to explain them. The most complete apparatus that is in 

 use, I think, is the one at the Royal Veterinary College. This 

 cost a lot of money, and is quite out of the reach of the amateur; 

 you will see by the slide how it is arranged. There are several 

 vertical instruments made. One by Van Heurck consists of 

 an oblong box, mounted on four legs of such a length that the 

 ocular end of the microscope passes through the bottom of the 

 box ; the box is large enough for the head to pass in for focussing 

 purposes. Another, designed by Mr. Pringle, has many advantages 

 over the solid box, as it is made with a conical bellows, and the 

 screen is made to slide down. For some objects a vertical camera 

 is necessary ; there are objects that you cannot keep flat unless 

 the stage of the microscope is horizontal. 



When one starts in this line or branch of photography there 

 are several points to be taken into consideration. First, there is 

 the apparatus — I should advise anyone who is beginning, to buy the 

 best and steadiest microscope stand that they can afford, and with 

 a sub-stage for the various fittings that will be wanted from time 

 to time ; the long bellows camera, with board, is not an expensive 

 part of the apparatus, and can be bought for ^3 or ^4. Then 

 come the lenses ; these are most important, and, like photographic 

 lenses, rather expensive articles to deal with, if one goes in for 

 high-power work. But I am not going to touch on this line, so 

 will leave it to others who go in for deep scientific research, such 

 as the different forms of bacteria. The Germans have, hitherto, 

 made most of the best lenses for photographic work, and sell 

 lenses with a focussing eye-piece for correction — lenses that have 

 given better definition, flatter field, light, and more even illumina- 

 tion which come about by the use of the new glass from Professor 

 Abbe, and again they are cheaper ; but now the English opticians 

 are beginning to wake up in this direction, and many lenses are 

 made that are quite as good and no more expensive ; in fact, I 



