22 



Paul Bunge, Hamburg. 



1. Physical Balance for a Maximum load of 2 Kilos., 

 (Fig. 1) with Abbe collimator telescope, reflecting prism and concave 

 mirror fitted to the beam, which magnifies the oscillations of the latter 

 about 25 times. The beam is made of the finest argentan. In order to 

 reduce the effects of currents of air the pans are built up of 9 crosses. 

 By reason of the telescopic arrangement the oscillations are very ra- 

 pid and constant. All the knife-edges and planes of the beam and 

 pans are made of agate. 



Length of beam 24 cm.; weighing space 17X32 cm. Degree 

 of sensibility: 5 degrees deflection in the telescope per milligramme., 

 or variable at will. The sensibility is constant for all charges. 

 Mounted on black glass or white marble plate. 



Fig. 2. 



2. Analytical Balance for a Maximum ^charge of 200 

 grammes (Fig. 2) with arrangement for mechanically charging or dis- 

 charging the weight-pan without opening the casing; with reading- 

 telescope. By means of sliding carriers having the values of the 

 respective weights marked on them each weight may be placed exactly 

 in the center of the pan, which consists of 17 concentric brackets 

 arranged one above the other; the mechanism is such that no vibra- 

 tion, friction or accidental dropping of weights can take place. By 

 turning a crank forward the frame supporting the carriers descends, 

 the carrier is liberated and may be withdrawn from under the weight. 

 The balance is thrown into action by turning the crank in the opposite 

 direction. As in this case the pointer swings out only one degree per 

 milligramme, the tenths of a milligramme may be read off in the tele- 

 scope directly and the hundredths may be estimated. The rapidity of 

 the oscillations has, therefore, in this balance been reduced in such 

 a way that it is to that of an equally sensible short beam balance 

 in the ratio of 1 : 1^10. The pan for the weighing charge is made 

 of rock-crystal. The rider slide is accurately notched on the dividing 

 engine. The pointer is of a triangular form to obviate vibration. 



Length of beam: 13 cm. Sensibility: 0.05 mg. 



Mounted on a clamped ma'hogony board or black glass plate. 



