EXPERIMENT STATION BULLETINS. 



483 



legged stand, with the lower end of the leg sharpened so that it can 

 be pushed into the ground sufficiently to hold the stand firmly upright, 

 and so that the top of the stand shall be approximately level. Upon 

 Ihe top of the stand a carpenter's level is placed and, by the use of wide, 

 thin wedges, adjusted to level. Over the top of the level thus adjusted 

 the operator may sight. Better still, sights may be attached to the level 



Fig. 1.3a. Illustrating the water level in use. 



Fig. 13b. Closer view of water level and carpenter's level. 



over which the operator may sight. Care must be exercised to adjust the 

 sights so that when the level reads level the line passing over the sights 

 shall also be level. 



The so-called water-level is illustrated in Fig. 13. It consists in this 

 case of two glass tubes firmly clamped to a bar attached to a sharpened 

 leg. The lower ends of the tubes are connected by a piece of rubber tub- 

 ing. A colored fluid is then introduced through one of the tubes until 



