1899] MICROSCOPICAL JOURNAL 157 



As my experience may be useful to others, I propose 

 to describe very shortly what it has been and in what 

 way I have succeeded in overcoming the diflBculties inci- 

 dent to the subject. My apparatus is a very simple one 

 and has been all constructed with my own hands. The 

 base-board of the apparatus is of yellow pine about 3 

 feet long, about 8 inches broad and l^^inches thick. I find 

 yellow pine much more rigid than a harder wood, and it is 

 much lighter. The camera is a quarter plate one, with a 

 bellows having an extension of about two feet. The end 

 of the camera carrying the dark slide is ridgidly attach- 

 ed to one end of the board, while the other end of the 

 camera, which is attached to a sliding front, can be 

 moved forward and fixed by a pinching screw at any dis- 

 tance within the limits of the bellows extension. The 

 top of the base-board at each side has narrow strips 

 screwed on within which the front of the camara slides. 

 The camera front has a flange screwed with the same 

 thread as the Dallraeyer half-plate R. R. and carries a 

 tube about 2 inches long which fits it. The microscope 

 is one which I specially made myself for the purpose. It 

 is mounted on two brass trestles which are rigidly screw- 

 ed to a board which slides within the guides on the top 

 of the base-board. The piece is about a foot long, and 

 it again can be pinched firmly at any position on the base- 

 board. The base-board for this purpose having a groove 

 reaching within 6 inches of each end. Beyond the mi- 

 croscope there is an upright board of thin wood which 

 has an aperture in it of an inch in diameter opposite to 

 the optical axis of the microscope. This aperture is used 

 for adjusting the size of the image wanted, and for focuss- 

 ing by means of a lamp of any kind placed behind it. A 

 small wooden shutter about 3 inches long, whose shape is 

 like that of a vertical section of a sugarloaf rotates at 

 the narrow end upon a screw nail while another screw al- 

 lows it to fall into position when the lamp is removed. 



