LEVELING 



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when the telescope is revolved slowly on the vertical axis of the 

 instrument. 



THE DUMPY LEVEL 



An engineers' dumpy level of American make is shown in 

 the accompanying illustration. In its general construction 

 it is similar to the wye level. The essential difference is that 

 in the dumpy level the telescope AB is attached rigidly to the 

 horizontal level bar CD, and the level tube EF is attached to the 



** 



level bar and is adjustable at one end and in a vertical direction 

 only, while the other end is attached permanently by a hinge. 

 Since the telescope cannot be revolved in its supports, there is 

 no necessity for the lateral adjustment of the level tube. 



Adjustments of the Dumpy Level. There are two adjust- 

 ments of the dumpy level, namely: 



1. To make the axis of the level tube perpendicular to 

 the vertical axis of rotation, so that the bubble will stand in 

 the center of its scale when the telescope is revolved. 

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