1046 



RECORD OF CURRENT RESEARCHES RELATING TO 



tlie main limb carrying the optical body, so that it may be inclined at 

 any angle. It is suggested that the ordinary method changes the 

 position of the centre of gravity of the instrument so considerably 

 as to render it more or less unsteady, while the new method avoids 

 the difficulty, and at the same time furnishes a secure and convenient 

 means of clamping the body at any position. 



Fig. 115. 



The stage and optical body are supported on the curved limb, 

 which is nearly a semicircle, as shown in the figure. This limb has 

 sectoral grooves about 90° in arc on either side, and slides between cor- 

 responding curved jaws, on the inner side of the upright pieces of the 

 foot. The foot itself is made in two symmetrical pieces fitting together, 



