83 
LUMINOSITY OF FLAMES CONTAINING SALT VAPOURS. 
Here 1 is the value of a for caesium chloride, 4'48 is the equivalent large concen¬ 
tration at which rubidium salts have conductivities equal to caesium salts at the large 
concentration unity, 121 is the equivalent weight of RbCl, and 168'5 that of CsCl. 
Also for RbCl 
121 
b = lOx 
168-5 
- 7’20 
where 10 is the value of b found for CsCl. 
c 2 —1 
To see if the equation 10 4 £ = - (b + ac ) would give results agreeing with 
Q> 
experimental values, using the values of a and b given above, a number of 
measurements of the relative conductivities at small concentrations were made. 
The following results were obtained with solutions of RbCl:— 
Solutions sprayed 
Ratio of 
(grammes RbCl per litre). 
conductivities. 
Flame A. 
Flame B. 
B/A. 
0-0202 
0 
0-178 
0-0202 
0-00202 
0-34 
0-0202 
0-0202 
1-30 
0-0202 
0-202 
4-32 
Taking the conductivity when spraying water equal to unity, these results give 
the following numbers :—- 
Solution sprayed 
(grammes RbCl per litre) 
(k). 
Conductivity • 
(found). 
k 
(calculated). 
0 
1 
0 
0-00202 
1-91 
0-0019 
0-0202 
7-30 
0-0219 
0-202 
” 24-2 
0-202 
The last column contains the values of k given by the equation 
2 1 
10 4 £ = —- (7'2 + 3'2c). 
c 
