28 The Philippine Journal of Science I9t7 



Table VI. — Decomposition of chloride of lime in fresh sewage (concen- 

 tration of chloride of lime expressed as milligrams of available 

 chlorine ) — Continued. 



C. EFFECT WITH CONSTANT VOLUME OF LIQUID (CONCENTRATIONS OF CHLO- 

 RIDE OF LIME EXPRESSED AS PARTS PER MILLION OF AVAILABLE CHLORINE). 



Series 8. 



; Added. | Left. j Consumed. | Left. ; 



4.6 1.9' 2.7 69 



9.2 



3.7 | 5.5 ; 60 \ 3.2 j 



18.4 I 7.3 j 11.1 J 60 j 10.6 



27.5 13.7 : 13.8 50 '' 13.1 

 45.8 j 16.4 ' 29.4 j 64 ! 28.0 

 64.2 I 5.2 ' 59.0 ! 92 I 27.5 ! 

 82.5 3.5 ; 79.0 ; 96 i 8.5 | 



184 j 41.0 j 143 I 78 i 21.1 



275 j 108 I 167 [ 61 j 91.1 



368 i 197 j 171 j 47 j 171 



460 ! 249 ! 211 i 46 | 258 



690 ' 445 ; 245 , 36 j 472 



920 707 213 ] 23 ' 690 



1,835 I 1,385 ; 450 j 25 j 1,415 



2,750 j 2,093 | 657 j 24 j 1,925 



4.580 3,615 | 965 ; 21 3,330 





Per cent. 



4.0 



87 



6.0 



65 



7.8 



42 



9.4 



34 



17.8 



39 



36.7 



57 



74.0 



90 



106 



96 



132 



95 



163 



88 



184 



67 



197 



54 



202 



44 



218 



32 



230 



25 



420 



23 



825 (?) 



30 



1,250(?) 



27 







The foregoing data show the peculiar fact that with increasing 

 additions of available chlorine the amount left after digestion 

 first increased, next decreased, and finally again increased. For 

 certain concentrations the available chlorine left after digestion 

 was greater with small additions of chlorine than with much 

 larger ones. The different series listed above were obtained on 

 different days with different samples of sewage, so that the 

 agreement between the results recorded is as good as is to be 

 expected. As a matter of fact, different samples vary greatly 

 and the same samples change with time, as indicated by the 

 differences between series 6 and series 7. 



Owing to the change in the volume of the digested liquid, 

 caused by large additions of chloride of lime solutions, discrep- 

 ancies in the analytical results may occur. In series 8 these 

 deviations were avoided by keeping the quantity of liquid constant 

 by the addition of enough water to the first members of the series 

 to compensate for the differences in volume caused by the ad- 

 dition of chloride of lime solution. 



Typical series in the foregoing table are graphically shown in 



