Oxygen dissolved in c.c. per litre at 0°C. and 760 mm. 
358 Messrs Purvis and Black, Oxygen content of the river com 
which had died or been removed, the increasing amount of 
dissolved oxygen observed from November 12 to December 8 
(see Fig. 3) is explained by the diminution in the amount of 
pollution which follows the decrease of the rainfall between those 
--—-- dissolved oxygen in c.c. per litre at 0°C. and 760 mm. 
hours of sunshine for the two days preceding that on which the sample was 
taken. 
Fig. 2. Curves showing the connection between the number of hours of sunshine 
and the amount of oxygen dissolved in the Cam in c.c. per litre, 150 feet above 
the effluent outfall. 
two dates, together with the fall in the temperature of the water 
from 20°C. on May 29 to 5°C. on December 8. The deter- 
minations by Winkler of the number of c.c. of oxygen held in 
solution in one litre of water are quoted in the 8th Report of 
EEE 
Hours of snnshine for the two vrecedines davs- 
