118 



PHOTO-MICROGRAPHY 



(iii) How to exclude light from junction of camera and microscope. — 



It will be seen on reference to Figs. 24A and b on page 54, that it is evident some 

 sort of arrangement must be contrived to keep the extraneous light from entering 

 the point of union of the microscope tube — ^wherein is placed the eye-piece — and 

 the camera. Several arrangements can be devised, one being to join up the gap by 

 tying a bag of velvet on to the projecting end of the microscope, and securing it in 

 turn to some suitable form of nozzle fixed on to the camera. We have given up this 

 arrangement in favour of the following, Fig. 61, which is far more satisfactory. It 

 keeps out all light and yet allows a limited amount of movement of the tube w^hich 

 is of course required when focussing the object. The dimensions are as follows ; — 

 That portion attached to the camera is i|- inch wide and 1^ long. It is joined on to a 

 flange, which fits on to the ordinary sliding front, whilst that fixed on to the draw- 

 Fig. 61 



Fig. 62 



Diagram of Base-board of Apparatus 



Diagram of Draw-Tube and Camera Ends 



tube of the microscope is if inch in diameter at its free portion, into which the 

 other passes, but reduced in diameter at its other extremity to fit the draw tube, 

 allowance being made for a cork lining to prevent it scratching the lacquer. 



(iv) How to fix Microscope on Baseboard. — Lastly the microscope must be 

 fixed on to the apparatus /rm^^/. In the expensive forms of apparatus this is fully 

 provided for, and is shown in the diagrams already given : but in our own arrange- 

 ment it is obtained by a special form of clamp, very simple, and easy to make. Three 



