296 II. A. Rowland et al. — Ratio of the Electromagnetic 



Before and after each series the times of vibration, t and T, 

 and the readings, /9 and a, were taken. The logarithmic decre- 

 ment was observed almost daily. 



Results. 



The table on the opposite page gives the results of all the 

 observations. 



These results can be separated according to the number of 

 discharges as follows : 



1. 



2. 



3. 



4. 



5. 



300-5 9 



298-37 



295-73 



296-43 



296-50 



300-17 



298-61 



296-40 



297-24 



296-37 



296-72 



297-43 



298-75 



301-82 



297-3S 



297-84 



297-78 



298-66 



295-02 



296-87 



298-90 



300-19 



296-75 



295-22 



296-31 



298-57 











299-05 











300-80 











296-56 











298-80 



298-48 



. 297-26 



297-15 



296-69 



In taking the mean, I have ignored the difference in the 

 weights due to the number of observations, as other errors are 

 so much greater than those due to estimating the swing of the 

 needle incorrectly. 



It will be seen that the series with one discharge is some- 

 what greater than with a larger number. This may arise from 

 the uncertainty of the correction for the greater number of dis- 

 charges, and I think it is best to weight them inversely as this 

 number. As the first series has, also, nearly twice the number 

 of any other, I have weighted them as follows : 



Wt, vxlO- 8 



8 298-80 



4 298-48 



3 297-26 



2 297-15 



1 296-69 



Mean » 29S-15 



Or v = 29815000000 cm. per second. 



It is impossible to estimate the weight of this determination. 

 It is slightly smaller than the velocity of light, but still so near 

 to it that the difference may well be due to errors of experi- 

 ment. Indeed the difference amounts to a little more than 

 half of one per cent. It is seen that there is a systematic fall- 

 ing off in the value of the ratio. This is the reason of my de- 

 laying the publication for ten years. 



