III. - MISCELLANEOUS. 625 



The cross staff and mirror hypsometer. 



The cross staff serves likewise for marking right angles and drawing per- 

 pendiculars. 



The inirror-hypsometer is used for measuring the height of trees, &c. 



These instruments are particularly useful for foresters and agriculturists, 

 on account of their being easily carried about. 



(See " Holzmessekunst," by Prof. Dr. Baur, Hohenhehn). 



3066. Small Universal Instrument for measuring heights, 

 &c., with stand. Zimmer Brothers, Stuttgart. 



Small levelling instrument and theodolite in one, for measuring heights, 

 horizontal angles, &c., and for levelling and marking right angles. Useful 

 to foresters and agriculturists, on account of its cheapness, and capability of 

 being easily handled. 



3067. Sextant of Aluminium, constructed by A. Petri, 

 Rostock. P ro f' H. Karsten, Rostock. 



3068. Hypsometer (tliermo-barometer), graduated in ^yths 

 of a degree centigrade, and in millimetres representing the 

 corresponding tensions of aqueous vapour. 



Will. Haak, Neuhaus am Renmveg, Thuringen. 



3O68a. Hypsometer, large, with thermometer. L. Casella. 

 3O68b. Hypsometer, small, with thermometer. L. Casella. 



3069. Hypsometer for levelling. To ascertain elevations up 

 to 500 metres by observing" the ebullition point of water. 



Prof. Helmert, Aix- la- Chape lie. 



3070. Hypsometer for levelling. To ascertain elevations up 

 to 4,550 metres by observing the ebullition point of water. 



Prof. Helmcrt, Aix-la-Chapelle. 



3071. Apparatus constructed for observing the ebullition 

 point of water, in the use of hypsometers. 



Prof. Helmert, Aix-la-Chapelle. 



3072. Distance and Altitude Measuring Theodolite, by 



Dennert and Pape, in Altona, with stand. 



Prof. Helmert, Aix-la-Chapelle. 



The theodolite is intended for topographical surveys. The division of 

 the circle is so fine that frequently the reading of one index will suffice, its 

 position being appreciable to 1 minute with the lens. As the stand can be 

 set up very firmly, the vernier arm is not movable together with a spirit level, 

 bur fixed. 



3073. Theodolite with two Vertical Circles. 



Geodetic Institute of the Royal Polytechnic School at 

 Munich, Prof. Dr. von Baucrnfeind. 



The Theodolite with two Vertical (Circles was made by Ertel & Son, of 

 Munich, from the exhibitor's design. It seems in the first place suited for 



39508. R r 



