Manchester Memoirs, Vol. Iv. (1910), No ?J. 



II. Note on Scattering during- Radio-active Recoil. 



By Walter Makower, M.A., D.Sc, 



AND 



Sidney Russ, D.Sc. 



Received and read November ijtii, igio. 



In the course of some experiments on the recoil of 

 radium B from radium A, it was found that not only did 

 a surface directly exposed to the recoil stream become 

 active, but surfaces situated outside the direct stream also 

 received active deposit. It was thought that these effects 

 were due to reflection or scatterinij from the surfaces 



Fig. I. 



upon which the recoil-atoms fell, and a few preliminary 

 experiments were made to test this hypothesis. The 

 experiments, which were carried out in a high vacuum, 

 were made in the following way. A plate S was mounted 

 as shown in Figure i in such a way that it was outside 



December j6t/i, igio. 



