PHENOMENA OF DRAINAGE WATERS 



207 



much weaker than that produced by ordinary showers, owing 

 to the large amount of little altered rain water which then 

 gains access to the drain-pipes. 



As a first illustration, showing the more ordinary relation 

 of the first and last runnings of the drain-pipes in Broadbalk 

 field, we may compare the composition of the waters collected 

 on the evening of June 2, 1879, about one hour after the pipes 

 had commenced running, with that of the waters collected on 

 the following morning when the pipes had nearly ceased 

 to run. 



TABLE XXXIV 



CHLORINE AND NITROGEN AS NITRIC ACID IN DRAINAGE 

 WATERS COLLECTED NEAR THE BEGINNING AND END 

 OF A RUNNING, IN PARTS PER MILLION 



The drainage waters from the different plots are seen to 

 differ much in composition, the differences being chiefly deter- 



