762 SEC. 15. GEOGRAPHY. 



feind's "Elemente der Vermessungskunde," 5th edition, Vol. T., pp. 168- 

 175, especially 173-175. Its object is identical with that of the subsequently 

 invented five-sided angle prism (No. 3097), which, as already stated, may be 

 used instead of it. 



3041a. Compass Binocular. Robert E. Barker. 



A small mariner's compass is fixed between the two tubes of the field-glass. 

 Inside of the cover of the compass case (which is hinged tightly at the edge 

 farthest from the eye, so as to remain set at any angle between and 90) 

 is a mirror. When the mirror is set at about 45, the direction in which 

 objects seen through the glass lie, is shown by merely raising the eye and 

 looking at the reflected image of the compass in the mirror. 



This combination will be of service to officers of the army or navy, also to 

 exploring parties, travellers, or tourists. With it the compass bearings of any 

 object in the field of the glass can be seen directly in the mirror attached. It 

 adds very little to the weight of the glass, can be fitted to any binocular, and 

 will readily go into the original sling case with it. Rough surveys may be 

 made with it in positions where larger and more costly instruments would not 

 be available. 



3Q42. Clinometer, by General Naeser. 



Survey Office, Christiania, Norway. 



This apparatus consists of a thin circular brass box, vertically fixed on 

 three screws, by means of which the exact position can be maintained. 

 Through the centre of the box moves an axis, supporting on one side a small 

 telescope, and on the other a needle, following the movements of the telescope, 

 and giving the readings of the tangential scale engraved on the box. By a 

 .small change-wheel, the angle between the optical axis of the telescope and 

 the horizon is multiplied 10 times, thus enabling the operator to read off the 

 tangent with sufficient accuracy. The horizontal distance between two ob- 

 jects being known, the difference in height can easily be found. The instru- 

 ment can be used with advantage for distances up to 15 miles, and generally 

 for all levelling purposes. 



3043. Clinometer, by G. Olsen. 



Survey Office, Christiania^ Nomvay. 



This apparatus consists of a square box, in which a pendulum moves on a 

 horizontal axis. At the lower end of the pendulum a tangential scale is fixed, 

 which doubly reflects in two small mirrors placed over the top of the pendu- 

 lum. On the outer side of the box a small telescope is fixed, movable in the 

 vertical plane. By directing this telescope to an object whose horizontal 

 distance is known, and by reading off the division on the scale that coincides 

 with the object, the difference in height can be readily found by referring to a 

 table. The instrument needs no corrections, is very handy, and easily trans- 

 ported, but cannot be used at such long distances as the clinometer con- 

 structed by General Naeser. 



3O43a. Casella's Improved Ship's Clinometer, for 



measuring the inclination of ships or yachts fore and aft or 

 athwart ship. L. Casella. 



3044. Pocket " Mensor." An improved arrangement or 

 combination of various instruments for measuring and other pur- 

 poses. Ridley Henderson. 



