loosening the leveling screws. To appropriate all the advantages 

 of the Q. L. H., loosen the leveling screws, turn the thickest 

 portion of the lower disc toward the down-hill side; hold 

 fast tc* this and turn the upper plate, with instrument, until the 

 thickest portions of both discs lie superimposed. Now tighten up 

 the leveling screws and finish the leveling operation with the level- 

 ing head, if necessary, as shown in Fig. 123. 



The great advantage of this type, particularly when used for 

 transits, lies in the fact that the instrument will not capsi/e though 

 the screws may be undamped, and no accident can occur on this 

 account. The illustration shows how the Q. L. H. may be shifted 

 on the tripod head for centering over a peg or under a "spud". 



The illustration shows by comparison the amount of inclina- 

 tion that may be overcome. It about doubles the tilt of the level- 

 ing base. If greater inclination is sought by means of the leveling 

 base alone, the lower dust guards for the leveling screws may be 

 unscrewed and removed. 



The base cups for the leveling screws are provided with spheri- 

 cal sockets that are in the same plane with the ball joint of the com- 

 pound center. The base cups are secured against loss with a small 

 loosely set anchor-screw. 





The Counterpoise Plummet 



The auxiliary telescope for mine theodolites 

 had been counterbalanced merely by a weight of 

 no other utility until we designed a plummet for 

 this purpose in 1910. The point is to be removed 

 when there is revealed a threaded hub that will fit 

 into either trunnion as in Fig. 105 or into the 

 special loop as in Figs. 95 and 106. The counter- 

 poise plummet (C. P. P.) weighs 12 oz. and can 

 be used for an extra plumb bob when not employed 

 as above. 



For mining and other surveys the adjustable 

 plummet with inside reel as shown in Fig. 186 has 

 been widely preferred and for surveys in w r indy 

 country the slender mercury plummet has also 

 had some popularity. 





