522 Prof. J. C. McLennan on the Relative Intensities of 



the penetrating radiation, or are they due to other influences 

 which have not been eliminated in the conditions of 

 measurement ? 



One of the best ways of answering these questions would 

 be for the same observer with the same instrument to make 

 measurements at points for which we have results which do 

 not agree, and measurements such as those recently made by 

 Simpson and Wright * on the ' Terra Nova ' and at all points 

 of call on their voyage to the South Pole, which are of that 

 charncter, will do much to clear up some of the obscure out- 

 standing points in connexion with the anomalous results at 

 present on record. 



IT. Observations on the Penetrating Radiation in Different 



Localities. 

 Some measurements made by the writer during a recent 

 stay in Great Britain, and during the voyage following to 

 Canada, also throw some light on one of the questions raised 

 above. 



In these measurements the arrangement of apparatus used 

 was the one adopted by the writer and by Wright f and 



Fig. 1. 



Cline % on different occasions at Toronto. It is shown in 

 fig. 1. The measuring apparatus was the well-known 



* Simpson & Wright, Proc. Roy. Soc. Ser. A, vol.lxxxv. p. 175 (1911). 

 t Wright, Phil. Mag. xvii. 1909. % Cline, Phys. Rev. xxx. 1910. 



