104 ‘THE WOODSMAN’S HANDBOOK. 
scale. These scales are struck from the same center and meet at 
a zero point, from which they are graduated outward in degrees to 
90. A measuring arm, having a spatulate lower end beveled to 
receive vernier graduations, sweeps these scales. This arm is car- 
ried by a short shaft journaled in the upper edge of the plate and 
concentric with the two curved scales. The outer end of the shaft 
is furnished with a knurled handwheel, by which the clinometer 
is operated. The inner end of the shaft carries a frame supporting 
the tubular case containing the spirit tube of the hand level, the 
center of the case being cut away to show the bubble in the tube. 
A jam nut for setting the instrument is applied to the extreme 
inner end of the shaft, and when turned inward holds the same 
Fig. 11.—Combined surveyor’s hand level and clinometer. 
against turning. The measuring arm and frame are rigid with the 
shaft, so that when the same is turned in either direction they turn 
together and to the same extent, the same as if of one piece. The 
case stands at a right angle to the measuring arm, so that when the 
arm is placed at the zero point of the two scales the case will be 
exactly parallel with the longitudinal axis of the hand level. 
A slot formed in the top of the main tube is located in line below 
the exposed middle portion of the spirit tube and in line above 
the mirror, and permits the bubble to be reflected in the mirror, 
which is so narrow and placed so close to the off side of the main 
tube that it does not interfere with the line of vision through the 
same and a view of the cross wire. 
