No. 517112. 



Fall Machines and Fall Apparatus. 



255 



51 791 and 51 728. 1 : 15. 



51 792. 1 : 12. 



cord roller of aluminium 100 g in weight, 2 dropping weights of 70 g, to which two 



weights each of 98 g can be screwed, 4 weights and 3 excess weights 



The machine is constructed with the very greatest care, and in addition to permitting of the de- 

 monstration of the laws of fall proper allows of all the experiments suggested by Weinhold on force, 

 mass and acceleration (W. D., pp. 74 and 75 [68 and 69]), without the use of friction weights. 



51.790. Fall Machine mounted in glazed Cupboard, Figure, travelling on rubber rollers, 

 otherwise as No. 51,789. Own new type 



This arrangement does away with the troublesome necessity of placing the machine in the 

 museum cupboard; the machine is always ready for use and easily accessible when the cupboard 

 is opened. 



51.791. Atwood's Fall Machine, Figure, with levelling screws, on iron wall bracket. 

 The fall posts are easily detachable. Without table, metronome or cell 



The roller, 100 g in weight, is of aluminium, is most accurately balanced, and runs on friction 

 rollers. The following belong to the apparatus: the two dropping weights of 70 g on to which two 

 98 g weights can be screwed; also 4 weights and 3 over weights, and electric release. The latter can 

 be operated by means of an electric metronome (see No. 51,726) or a Morse key. 



51.792. Fall Apparatus and Seconds Pendulum, with simultaneous electric release (as sug- 

 gested by Edelmann), Figure (Physikal. Ztschr., 1903, p. 413) 



The falling ball and the body of the pendulum are held fast by an electric magnet, being released 

 simultaneously when the circuit is opened. The ball falls exactly on the pendulum body. 



s. d: 

 16.10.0 



22.10.0 



12. 0.0 



2.15.0 



Cl. 457, 459, 5383. 



