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Spirit-Levels on Metal Base. 



No TE. For use in setting weirs, fine machinery etc., and for leveling up apparatus in observatories ami 

 physical and chemical laboratories, etc. 



Ground Spirit -Level, one division of level about 1 min. of arc ; mounted on 34 

 inch metal base, provided with a handle. Level adjustable. In case. 



Price $7.OO 



Ground Spirit- Level, one division of level about 30 sec. of arc ; mounted on 

 8-inch metal base, provided with a handle. Level adjustable. In case. 



Price $13.OO 



Locke's Hand-Level. 



Brass or nickel-plated. In case 



Price $8.OO 



NOTE. This consists of a brass tube 6 inches long, with a small level mounted on its top to the left of its 

 center near the object end. Underneath the level is a horizontal wire stretched upon a frame. This frame is 

 made adjustable by a screw and a spring working against each other, or by two opposing screws placed at the ends 

 of the level mounting. In the tube directly below the level is placed a totally reflecting prism, acting as a mirror 

 set at an angel of 45 to line of sight. The images of the bubble and wire are thus reflected to the eye. 

 The prism divides the aperture in two halves, in one of which is seen the bubble and wire focussed sharply by 

 a convex lens placed in the draw tuba, while thz other permits of an open view. Putting the instrument to 

 the eye and raising and lowering the object-end until the bubble is bisected, natural objects can be seen through 

 the open half at the same time, and approximate levels can then be taken. To prevent dust and dampness 

 from entering the main tube, both the object and the eye ends are closed up with plain glasses. In preliminary 

 work this is a very useful instrument. 



a 



Hand-Level and Clinometer. 



Abney Level and Clinometer. 



Price $14.OO. 



NOTE. This instrument is similar to the Locke's hand-level, but the small spirit level mounted on top 

 can be moved in the vertical plane and clamped to a dial graduated in single degrees, thus the angles of slopes, 

 etc., can be measured also. 



