138 Mr. L. Simons on the Beta-Ray Emission from 



Table III. has been prepared according to this latter 

 scheme, and the results show a very much better agreement 

 than is shown by Table II. prepared from the former scheme- 



Table III. 









! 



Incidence of Silver (K) 



Incidence of Barium (K) 











X-rays. 







X-rays. 





















Screen 



vl 



h,- 



Kinetic 







\ Kinetic 







(8). 







en erg v 

 (E)of 

 sub- 

 group 

 +n h. 



Range 

 cm. 



E/VZ*. 



+n h. 



1780 



energy 

 (E)of 

 sub- 

 group 

 + n h. 



Eange 

 (d). 

 cm. 



E/dK 



+ n h. 



*.- 



L. 



a 



As ... 



783 





1 850 



0-228 



1600 



0-595 



2070 



Se ... 



835 





798 



0193 



1820 



1548 



0-455 



2300 



Zr ... 



1156 





477 



0-157 



1200? 



1227 



0-438 



1860 



a? ... 



1633 





... 







750 



0-140 



2010 



Sn ... 



1871 



254 



1379 







512 



0-128 



1430 



Sb ... 



1950 



265 



1368 







433 



0-070 



1640 



Ba ... 



2383 



328 



1305 



0-333 



2260 









Au ... 





717 



916 



0175 



2190 



1666 



0-595 



2160 



Pb ... 





777 



856 



0-164 



2110 



1606 



0-560 



2150 



Bi ... 





797 



836 



0-164 



2070 



1586 



0-427 



2430 



As ... 





... 



1618 



060 



2090 



2368 



1-0 



2370 



Mean of all the values of E/f^-Hz £ = 2C00. 



Table III. — Columns 2 and 3 are taken from Table I- 

 Column 4 is obtained from the expression 



A>/ ?i o)K a - 9 W»o) Ea orL a ' 



the value for K a being employed in the latter term for those 

 screens of atomic number lower than that of Silver.. 

 Similarly, column 7 is obtained by substituting Bsb (v!n ) K for 



the former term, and employing the values for K a in the- 

 latter term for those screens below the atomic number of 

 Barium, and L a for those above that of Barium. The values 

 of As at the end are taken from Table 1. 



It will be seen that the values for the constant agree very 

 much better among- themselves than is shown in Table II. 



Taking m = 8-8xl0- 28 gm., a=2'lxl0 40 in air at 0° C. 

 and 76 cm. pressure (within an accuracy of 15 per cent, 

 according to Whiddington), ?/ = 3-3x 10 15 sec. -1 (Rydberg's- 

 constant), h = 6'6 xl0~ 27 erg. sec. (Planck's constant), we 



