256 



Mr. A. S. Eve on the Ionization of 



One or two notes are added on some results obtained by the 

 Ebert instrument. 



I. 



The Ionization of the Air in the Physics Building, 

 McGill University. 



It may be of interest to note the effect o£ the presence of 

 radioactive matter and emanation on an Ebert instrument. 

 Observations were made in various rooms in the Physics 

 Building. The supply of radium is kept mainly in the 

 basement. For comparison, readings were taken oat of doors, 

 and in the Chemistry Building into which radium has not 

 been introduced. 



The effect both of the direct rays and of the emanation of 

 radium in the Physics Building is well marked. 



March 17, 1906. 



Place. 



Chemistry Building 



Physics Building, basement 



„ „ top floor 



,, ,, room, top floor 



,, ,, Lecture Theatre, 2nd floor... 



Out of doors, on College Campus 



Physics Building, Workshop, ground floor 



Time. 



?i + . 



u_. 



9.30 a.m. 



1760 



1550 



11.00 „ 



66G0 



6300 



11.20 „ 



3660 



2740 



11.40 „ 





2080 



12.15 p.m. 





3640 



2.30 „ 



1690 



1642 



3-00 „ 



7160 



4900 



II. 



The Effect of Smoke. 



On another occasion a bee-keeper's smoker, consisting of a 

 pair of bellows, with a chamber for burning tobacco, rags, or 

 paper, was used to blow dense clouds of smoke around the 

 Eberfs apparatus. 





| . + . 



i>> . 



No smoke 



1778 



1590 

 1000 



With smoke 



' 1270 



No smoke , 



"OHO 





