HAND AND OTHER APPARATUS. 45 



tended to support the oblong board to which the 

 camera is fastened ; a binding screw and a brass slip 

 working in a slot cut down the centre of the beam 

 attaches them to each other. 



On the second division, 2, a platform of sufficient 

 height to enable the microscope to be adjusted to 

 the camera is erected, the microscope being pre- 

 viously firmly attached to a separate board, slid- 

 ing to and from the lamp, between two grooved 

 slips on the top of the platform. This should also be 

 clamped in position by a binding screw. 



Owing to the different forms of microscope stands 

 it is impossible to adhere to any fixed rule with regard 

 to the method of attaching the microscope to the 

 platform. It must, however, be as accurately and 

 firmly fastened as possible, while its motion to and 

 from the lamp must take place without disturbing 

 the centering of the different instruments. 



A thick board the same width as the stand and 

 about twelve or fourteen inches long, is fastened at 

 right angles to plank No. 3 on the extremity behind 

 the lamp ; an aperture six inches square being pre- 

 viously cut in it, on a level with the top of the plat- 

 form to which the camera is attached. This aperture 

 enables direct sunlight to be used, with the appara- 

 tus in the horizontal position. 



A division about quarter of an inch wide, runs 

 along the centre of the plank to within two or three 

 inches of its extremities, this enables the lamp, bull's 

 eye condenser, and sulphate of copper cell to be 

 firmly clamped in position by binding screws. 



