548 Intelligence and Miscellaneous Articles. 



I transcribe here only two of the very numerous series of experi- 

 ments I have made, reminding the reader that all the balls fell from 

 the same height upon the plane surface of steel. 



Deviation at the Galvanometer. 



Ball. 1st series. 2nd series. 



Steel 72-5 84'2 



Copper 94-2 115-0 



Zinc 111-0 130-0 



Brass 110-5 127 



Silver 112 130 



Tin 164 194 



Lead 270 320 



The first series were performed on the 11th, and the second on 

 the 22nd of January. 



As general result we may deduce from these two series that the 

 duration of collision increases when the coefficient of elasticity dimi- 

 nishes. A closer connexion appears between the duration of collision 

 and the coefficient of elasticity when we form the product of that du- 

 ration and the square root of the coefficient of elasticity of each ball. 

 In this way we obtain the following Table : — 



Ball. 



Series 1. 



Series II. 



Ve. 



a. 



a Ve. 



Corr. 



a. 



aVE. 



Corr. 



Steel 



140 



102 

 933 

 92-4 

 84-5 

 63 

 42 



•725 

 •942 

 1-110 

 1-105 

 M2 

 1^64 

 2-70 



101-6 

 96-1 



103^6 



102-1 

 94-6 



103 



113 



+ 0-5 

 + 5-9 



- 1-6 

 + 0-1 

 + 7-4 



- 1 

 -11 



•842 

 M50 

 1-30 

 127 

 1-30 

 r94 

 3^20 



117-9 



117-3 



121^3 



117-4 



1100 



122 



134 



+ 2^1 

 + 2-7 



- 1-3 

 + 2-6 

 4-10 



- 2 

 -14 



Copper 



Zinc 



Brass 



Silver 



Tin . ... 



Lead 





Mean... 1020 



Mean... 1200 



From this Table M^e are justified in concluding that, when a series 

 of elastic bodies strike the same elastic surface, the durations of the 

 impacts are inversely proportional to the square roots of their coeffi^ 

 cients of elasticity. 



Ail the metals operated on conform to this law with sufficient ap- 

 proximation, except the ball of silver and that of lead. With respect 

 to the latter, this ought not to surprise us ; for the elasticity of lead 

 is so slight that even with our small heights of fall the limit of elasti- 

 city is considerably exceeded. As to the silver ball, Me must suppose 

 that its coefficient of elasticity is sensibly greater than that of the 

 substance on which the measurement of the coefficient has been 

 made. This supposition is by no means inadmissible when we con- 

 sider the very notable divergences on this point between the results 

 of different observers. — Bibliotheque Universelle, Archives des Sciences 

 Phys. et Nat. vol. xliv. pp. 335-338. 



