C. F. Betting, Kassel. Otto Bohne, Berlin. ,11 



No. 2751. 



C. F. Betting, Wehlheiden nr. Kassel. 



Mechanical Workshops. 



k 



Exhibit: Analytical Balance for a charge of 200 grammes, 

 with mechanism for charging and discharging the weight pan without 

 opening the case. 



By this mechanism substances may be- weighed quickly and accu- 

 rately and with ease. The substance which is to be weighed is placed 

 upon the pan on the left, the case is then closed and the weights are 

 placed upon the pan by simply turning the milled heads projecting on 

 the outside of the case. The latter remaining closed during the entire 

 operation of weighing, disturbances arising from changes of temperature 

 and currents of air are obviated. The weights, which range from 

 100 grammes to 1 centigramme, remain in the casing. Milligrammes 

 and fractional parts thereof are weighed by means of the riders. The 

 weight of the object having been determined by the mechanical weights 

 only a second set of weights is required for double weighing, the re- 

 spective weigths being introduced with opened case. The balance has 

 a sensibility of 0,1 milligramme. The beam is made of aluminium, the 

 other oscillating parts of thickly gilt brass. The planes are of carneol. 





No. 2752. 



Otto Bohne, Berlin S., 



90 Prinzen-Strasse. 



Aneroid -Barometers, Registering Barometers, 

 Thermometers and Hygrometers. 



The Aneroid-Barograph which is shown in Fig. 1 at x / 4 full 

 size, is indisputably the most correct instrument for metereological ob- 

 servations. It indicates not only, like the ordinary barometer, the 

 height of the barometer at any particular moment, but also records 



