88 A MANUAL FOR NORTHERN WOODSMEN 
corresponding bearings on the telescope tube, the pivot 
rings. The telescope can be lifted out of the wyes by lift¬ 
ing up the clips over the rings. The attached bubble 
enables the line of sight in the telescope to be brought 
into a horizontal position. 
The Level 
1. Adjustments of the Level 
(a.) Make the line of sight coincide with the axis of 
the pivot rings. Pull out the pins which hold the clips on 
the telescope and turn the clips back so that the telescope 
is free to turn in the wyes. Sight the intersection of the 
cross-hairs at some well-defined point. Then rotate the 
telescope 180 ° in the wyes, so that the bubble tube is above 
the telescope. The intersection of the cross-hairs should, 
still be on the point. If not, move the horizontal cross¬ 
hair half-way back to its first position by means of the 
upper and lower adjusting screws of the cross-hair ring. 
Then move the vertical cross-hair half-way back to its 
first position by the other pair of screws. Repeat the test 
until the adjustment is perfect. 
(b.) Place the line of sight and the bubble in the same 
vertical plane. Bring the bubble to the center of the tube. 
Revolve the telescope a few degrees in the wyes and note 
the action of the bubble. If it runs to one end, bring the 
tube under the axis of the telescope by means of the lateral 
