38 1 Intelligence and Miscellaneous Articles. 



which agreed with what we had found. We alluded to the fact 

 that Bragg and Madsen had obtained a similar 2 : 1 ratio ; but, as 

 ProFessor JBragg has pointed out to me, secondary penetrating 

 rays cannot have been the cause of their results, which they ascribe 

 to variation in the absorbabilities of (secondary) /3-rays in different 

 materials. A part of our variation must be similarly accounted 

 .for, so that whether secondary penetrating rays had any influence 

 remains to be proved. 



Glasgow, July 5th, 1910. Frederick Soddy. 



To the Editors of the Philosophical Magazine. 



Gentlemen — June 21, 1910. 



In a paper entitled " On the Electrostatic Effect of a Changing 

 Magnetic Field" by J. M. Kuehne appearing in the April 1910 

 number, the author attributes to me an effort to observe this 

 effect described in my paper published in the Physilcalische Zeit- 

 schrift (vi. p. 474, 1905). In my paper I distinctly disclaimed any 

 effort to observe this effect, and pointed out that the experiment 

 aimed to show that a plan suggested by Kolacek could not be 

 expected to yield any positive results. 



Very truly yours, 

 Johns Hopkins University, J° H * B - WHITEHEAD. 



Baltimore, Md. Professor of Applied Electricity. 



To the Editors of the Philosophical Magazine. 

 Gentlemen, — May 25, 1910. 



In connexion with my note " On the Laws regarding the 

 Direction of Thermo-electric Currents enunciated by M. Thomas " 

 (Bulletin de la Classe des Sciences of the Academie Royale deBelgique, 

 ]S T o. 8, p. 903), which appeared in the April number (Phil. Mag. 

 xix. p. 508), Professor E. van Aubel, of the University of Ghent, 

 has called my attention to a note of his in the " Chrouique et 

 Correspondance " columns of the Paris Revue generate des Sciences 

 for December 30th, in which the observations of Jager and 

 Diesselhorst are used to disprove the laws promulgated by 

 M. Thomas in almost the same way as I use them in my note. 

 I regret that I was not acquainted with Professor van AubePs 

 note when I sent mine to the Physical Society of London on 

 January 8th, as I should have been glad to kuow that the dis- 

 agreeable duty of criticising M. Thomas's theory had already been 

 discharged. 



I am, Tours truly, 



Charles H. Lees. 



