Alleged Scattering of Positive Electricity by Light. 437 



When only the number of the possible groups for a given 

 degree is required, and when n is a large number, it is very 

 desirable to avoid assigning so many different values to n as 

 are necessary if we employ the given formula. By observing 

 that all the fractions in this formula are increased by integers 

 when n is increased by 6, we may readily find the following 

 formula. By means of it we can find the number of 

 groups (N) directly for any value of n. m represents any 

 positive integer, and a x represents the largest value of a, i. e. 

 the largest integral value of x which satisfies the relation 



n 



r 



When n=§nij 

 „ n=6m + l, 

 „ n=6m + 2, 



N=m(3m 2 + 6m + l) 



^r m(6m 2 + 15m + 5) 

 2 



N = 3m(m + l)(m + 2) + l 





„ ti= 6m + 4, 

 „ n= 6m + 5, 

 Hence there are 



N=(m + l)(3m 2 + 9m + 4) 



H _ 3(m + l)(2m 2 + 7m + 4 ) 

 2 



4(96 + 60 + 5) , _. „_ . , R . 



— a + 24 = 64:6 groups of degree 50, 



249.84.85 + 1 + 500 = 1,778,361 „ „ 1000, &c. 



Ziiricli, Switzerland, March 1896. 



XLYI. On the alleged Scattering of Positive Electricity by 

 Light. By J. Elster and H. Geitel *. 



THE question whether light which facilitates the passage 

 of negative electricity from a conductor into the sur- 

 rounding gas can, in like manner, accelerate the discharge of 

 positive electricity is not without significance for the proper 

 apprehension of the photoelectric process. 



* Translated from the Ann. der Physih und Chemie, Bd. lyii. (1896) ; 

 from a separate impression communicated by the Authors. 



