322 



Sir E. Rutherford on Radium Constants 



In the following table the various magnitudes involving 

 the radium standard are expressed in terms of the Inter- 

 national Standard. 



Original paper. 



' Radio- 

 active 

 Sub- 

 stances.' 



Quantity. 



Rutherford & 

 Boltwood 

 Standard. 



International 



Radium 



Standard. 



Rutherford & Bolt- 

 wood, Auier. Jour. 

 Sci.xxii.p. 1 (1906); 

 Boltwood, Arner. 

 Jour. Sci. xxv. p. 269 

 (1908). 



pp. 16, 

 462. 



Amount of radium 

 in equilibrium 

 with one gram of 

 uranium. 



3-4 X 10-7 gr.Ra. 



3-23x10-7 

 gr. Ra. 



Boltwood & Ruther- 

 ford, Wien. Ber. cxx. 

 p. 313 (1911) ; Phil. 

 Mag. xxii. p. 586 

 (1911). 



p. 557. 



Production of 

 helium per gram 

 of radium per year. 



Calculated value ... 



156 c.mms. 

 155 c.mms. 



164 c.mms. 

 163 c.mms. 



Rutherford & H. 

 Robinson, Wien. 

 Ber. Oct. 1912; 

 Phil. Mag. xxv. p. 

 312 (1913). 



pp. 578- 

 581. 



Total heating effect 

 of one gram of 

 radium and its 

 products in equili- 

 brium with it. 

 Radium alone 



Emanation ,, 

 • Radium A „ 

 Radium B "1 

 Radium C J " 





134'7 gr. cals. 

 per hour. 



25*1 gr. cals 



per hour. 

 28-6 „ „ 

 30-5 „ „ 



50-5 „ „ 











Rutherford, Phil. 

 i Mag. xvi. p. 300 



1 (1908). 



p. 480. 



V olume of the ema- 

 nation from one 

 gram of radium in 

 equilibrium. 



Calculated value ... 



•60 c.mm. 

 •59 „ 



*63 c.mm. 

 •62 c.mm. 



Rutherford & Geiger, 

 Proc. Roy. Soc. A. 

 lxxxi. p. 141 (1908). 



pp. 128- 

 133. 



Number of a par- 

 tides expelled per 

 second per gram 

 of radium itself. 



Number per second 

 from one gram of 

 radium in equili- 

 brium. 



3-4x1010 

 13-6x1010 



3-57 X 1010 

 14-3x1010 



Rutherford & Geiger, 

 Proc. Roy. Soc. A. 

 lxxxi. p. 162 (1908). 



pp. 135- 

 137. 



Total charge car- 

 ried by the « par- 

 ticles per sec. from 

 one gram of ra- 

 dium itself and 

 from each of its 

 products in equili- 

 brium with it. 



31*6 e.s. units. 



105x10-9 

 e.m. units. 



332 e.s. units. 



1-11x10-9 

 e.m. units. 



