A Radioactive Gas from Crude Petroleum. 499 
obtained from one of the wells belonging to Mr. A. C. 
Edward, of Petrolia, Ontario, to whom my most sincere 
thanks are due for many samples of oil supplied during the 
course of the investigation. The petroleum from this locality 
is drawn directly from the Corniferous limestone, which lies 
at a depth of 465 feet below the surface, and, while it may 
possibly originate in these rocks, there are reasons for con- 
- cluding that the oil has its source in a deeper stratum, very 
probably in the underlying Trenton formation. j 
Bis, 1. 
To Water Purnp To Battery 
Lo Earth 
The petroleum to be tested was contained in a large three- 
litre flask D (fig. 1), supported in a water-bath. This flask 
was connected to a wash-bottle EK, partly filled with con- 
centrated sulphuric acid, and to a second flask F, embedded 
in ice for the purpose of condensing any vapours from the 
heated oil. The tube G was filled with phosphoric pentoxide, 
and the tube H tightly packed with glass-wool. The vessel 
A, made of thin galvanized iron, 62 cms. long and 25 cms. in 
diameter, was provided with an exploring electrode C, which 
was supported by an ebonite plug carrying a guard tube B. 
The rod C was connected to one of the pairs of quadrants of 
a quadrant electrometer of the Dolezalek type, whose sensitive- 
ness was such that a potential-difference of one volt between 
the quadrants gave a deflexion of 1100 mms. on a scale at a 
distance of one metre. Throughout the experiments, the 
cylinder A was maintained at a potential of 168 volts by a 
battery of small storage-cells, and the conductivity of the gas 
which it contained was determined by measuring the satura- 
tion current to the exploring electrode. This saturation 
current, when the cylinder A was filled with ordinary dry 
2M 2 
