Manchester Memoirs, Vol. lit. (1908), No. 14. 17 



effect of chlorophyll even in dilute solution is extraordinary. 

 If the sunstroke effect were dependent upon the photo- 

 chemical effect a very thin layer of chlorophyll containing 

 material should be a perfect protection. 



The Effect of Sunlight on Chloride of Lime Solutions. 



In considering the effect of cloride of lime as a 

 sterilising agent for sewage effluents, it is important to 

 investigate the stability of its solutions under various 

 conditions. 



It was found that dilute solutions of chloride of lime 

 lose their available chlorine with extraordinary rapidity 

 on exposure to Calcutta sunlight. 



Thus a solution of chloride of lime containing 45*5 

 milligrams available chlorine per 100 c.c, lost 18 milligrams 

 or nearly 40 per cent, of the available chlorine on 

 exposure for one hour on April 21st, from 3-45 to 

 4-45 p.m., a day when, as can be seen from Table III., the 

 chemical activity of the sunlight was only about two- thirds 

 of its maximum. 



On April 27th, when a maximum reading, viz., 26'0, 

 was obtained by the iodine test, a solution of chloride of 

 lime, containing 85 mgms. chlorine per 100 c.c, lost 

 34"6 mgms. or only slightly over 40 per cent, on one 

 hour's exposure, indicating that the tendency to de- 

 composition decreased with increase of strength of the 

 solution. The same solution on keeping for one hour in 

 the dark, and on being held for lO minutes in boiling 

 water, suffered no decrease in strength. 



These experiments were subseqently confirmed by 

 Captain, now Major Clemesha, Deputy Sanitary 

 Commissioner for Bengal. 



