So 



It is necessary that the specimen should bo exactly opposite the 

 centre of, and parallel to, the lens, otherwise the photographic result 



will be distorted by violent perspective. I rack the camera out nearly 

 as far as it will go, and then move it further from, or nearer to, the 

 object, till I get it rouylily in focus, finishing off with the rack and 

 pinion. Use the largest aperture of the lens to focus with, and then 

 stop down to get the necessary sharpness. This arrangement is simple 

 and excellent, unless you wish to enlarge to scale, when, of course, 

 more care must be used, such as measuring the image on the focussing 

 screen, &c. With r45 stop, and an ordinary rapidity isochromatic dry 

 plate, I find 30 minutes' exposure, in a large bay window, about right 

 for a dark coloured beetle. I give this time merely as a rough guide, 

 as, of course, exposure depends so much on the actinic power of the 

 illuminant, and the colour of the specimen. At night, with the object 

 lighted with lamps, the exposure would pi'obably be treble or more. 

 If, after all due care has been exercised with regard to the lighting, 

 you still have slight shadows, they can be blocked out from the 

 negative with ordinary sepia (moist water colour) thinned to the 

 consistency of cream with black writing ink, and applied carefully 

 with a camel's hair pencil. 



When I wish not to enlarge, but to photograph an insect natural 

 size, I proceed as follows: — Say the camera we are using is what is 

 known as a | plate, cut a sheet of white card exactly the size of the 

 plate, in this case, 6| in.x4f in., and place it opposite the lens (as 

 the drawing block is placed for enlarging), and focus it till it precisely 

 Jills the ground glass or focussing screen. On pinning the insect in 

 the centre of the card it will be found, on the screen, to be practically 

 the natural size. This dodge saves measuring, or any trouble of that 

 kind. I generally print my results on gelatino-chloride paper, com- 

 monly known as P.O. P., matt or glossy, but as they are enlarged 

 negatives, any printing process will suit. 



Lantern slides can, of course, be made from the negatives by 

 reduction or contact with little trouble. I usually glaze my prints, as, 

 though perhaps not artistic, it brings out the detail, which is what we 



