48 A FEW CHEMICAL CHANGES. 



tion was only at the surface next the air, for on scraping the 

 surface of the rod with a knife, the inside was found to have 

 the yellow colour of brass. While allowing the radium to act 

 on hydrogen peroxide in the experiment previously described, 

 where the brass rod was enclosed in an atmosphere of ozone, 

 and ,air containing more oxygen than ordinary air. there was 

 found on the part of the rod near the radium, a small quantity 

 of this dark grey substance. Some of this was scraped off, care 

 being take'n not to remove any of the brass. On analyzing this 

 substance it was found to contain only copper, there not being 

 even so much as a trace of lead or zinc present. What has 

 probably taken place is that the action of the radium on the 

 brass in the prese'nce of oxygen has slowly converted the copper 

 of the alloy to copper oxide; the greater the amount of oxy- 

 gen present the more rapidly the change takes place. 



The results here given show that i'n many reactions the effect 

 of radium is to accelerate that action already going on, and in 

 the case of amygdalin and hydrochloric acid it may perhaps set 

 up a new >action of its own, besides accelerating the hydrolysis 

 of the amygdalin into glucose, etc. Lastly the presence of 

 amygdalin may be detected by boiling a solution supposed to 

 contain it with a few drops of Eehling's solution "and noting 

 whether or not the odour of ammonia is given off. 



The author's best thanks are due to Professor MacKay for 

 the interest he has shown in these experiments. 



DALHOUSIE UNIVERSITY, Halifax, X. 8. 

 March 30, 1908. 





