Work, Mechanical Effect. FaU Apparatus. 



253 



51 781. 1 : 15. 



51782. 1:15. 



51.777. 2 Fall Cords (Babinet's) (Bohn, Physikal. Apparate aus d. Schaeffer-Museum, Nr. 25, 

 p. 19; Kleiber, Lehrb. f. Gymnas., 3 rd Edition, Fig. 373) 



Of the two cords one is loaded at a distance of 0, 0.5, 2, 4.5 and 8 m from the end with a 

 wood ball. The cord is suspended in a stepped chamber and allowed to fall. The balls reach the 

 floor simultaneously. The reverse experiment is carried out with the second cord weighted at the 

 same intervals. 



51.778. Fall Pipes (Newton's), see section dealing with Air Pumps and Accessories. 



51.779. Rail Apparatus (Hofler's), see No. 51,807, p. 258 



51.780. Fall Apparatus (Barrel's) for determining the time of fall of a sphere by allowing 

 a large number of balls to fall immediately after each other (Aldous, Elementary 

 Course of Physics, London, 1900, p. 46, Fig. 22) *. 



A ball falling freely actuates the electric releasing device of the next ball at the moment it en- 

 counters the end of its path of fall, so that a fresh ball commences to fall as soon as the previous 

 one has traversed the path of fall. The number of balls are calculated which fall from a certain height 

 in a given time, this number being divided into the time: the experiment is then repeated at different 

 heights of fall. 



51.781. Atwood's Fall Machine, Figure, as suggested by Weinhold (W. D., Fig. 64 [59]), 

 with polished scale board, on firm iron stand with levelling screws, device for releasing 

 the fall weights, catch for the excess weights, and receiving platform: with two fall 

 weights composed of 3 single weights of 70, 98 and 98 grammes; with cord pulley of 50 g 

 moment of inertia; with 4 weights, 3 excess and 3 friction weights. In addition to per- 

 mitting of the carrying out the demonstration of the laws of fall proper, the machine 

 can be used for all experiments on Force, Mass and Acceleration suggested by Wein- 

 hold 



51.782. - - i d e in, with seconds pendulum on the stand, in Cardan's suspension and with 

 audible seconds beat, Figure 



The pendulum is also suitable for explaining the pendulum laws; this remark also applies to 

 the succeeding items. 



s. d. 

 0.10.0 



11. 0.0 



4. 0.0 



3. 0. 



4. 10. 



CI. 455, 462S, 456. 



