26 



The Philippine Journal of Science 



Almost without exception the experimental results vary from 

 the calculated values by quantities well within the range of ex- 

 perimental error. Apparently this regularity holds good for 

 wide ranges of concentration with many different substances. 2 

 Even with fairly pure natural waters similar results may be 

 obtained under certain conditions. Thus 100 cubic centimeter 

 samples of a clear river water, boiled with varying amounts of 

 filtered chloride of lime solution for fifteen minutes in diffused 

 daylight, reacted as follows: 



Table V. — The interaction of a river water and varying quantities of 

 chloride of lime solution at 100° C. 



Chloride 



Chloride of lime of lime 



added as — Iconsumed 



mg. 



I 0.52 



J 0.49 



| 0.96 



| 0.84 



I 1.68 



1 1.82 



The ratio of the amounts of chlorine consumed is approximately 

 the same as that of the amounts added, namely, 1:2:3. 



With sewage there is a similarity of reaction, with some curious 

 differences. The percentage of chlorine consumed may increase 

 with increasing additions of chloride of lime, giving rise to the 

 peculiar phenomenon that the available chlorine left is greater 

 after digestion with small quantities of chloride of lime than 

 after digestion with much larger quantities for an equal period 

 of time. This observation was repeated too frequently to be cap- 

 able of explanation on the ground of experimental error, though 

 some series showed these abnormalities to a lesser degree than 

 others. 



This irregularity in chlorine consumption is also evident in 

 the data of previously published work. For example, Glaser (5) 

 says in effect: 



As a matter of fact, there are at hand several experiments which deviate 

 from the regular order, for instance, the progressive decomposition with 



"Avery and Lye (1) found that upon the addition of alum to water the 

 available chlorine was apparently reduced, within certain limits, in direct 

 proportion to the amount of alum added. 



