riTAI.K WATT'.i; TX HERTS. 13 



obviously supplied to a considerable extent by the underground 

 drainage from the upper part of the basin. This underground 

 drainage water when it passes Haiiiendcn contains about 11 of 

 chlorine per million of water; but as it continues to percolate 

 through masses of chalk at a great distance from the surface, it 

 may be assumed to gain chlorides from the small residue of common 

 salt remaining in the rock ; so that wells in the lower part of the 

 basin should, on an average, contain water richer in chlorides than 

 wells at the edge of the basin." 



He then speaks as follows of the water in the Chalk obtained 

 fi'om wells in the London Clay district : — " The clay has of course 

 prevented any percolation of rain from above ; the washing of this 

 chalk has therefore for many ages been confined to the slow passage 

 through it of water from the upper part of the basin, already con- 

 taining chlorides." In consequence of this, water in wells far from 

 the sea shows a richness in chlorides. 



It seems to me that the above is a good explanation, and the 

 more so as it accounts for like occurrences (sometimes of a stronger 

 kind) in other formations than the Chalk. The washing out of the 

 salts from the Chalk from the escarpment downward to the central 

 parts of the basin, where concentration would take place ; the 

 possible addition there of salts derived from the Tertiary sands 

 (between the London Clay and the Chalk) ; and perhaps some 

 chemical changes slowly brought about in the deep-seated water : 

 these would seem to be enough to account for the great differences 

 in the mineral contents of the waters in the open and in the 

 covered Chalk. 



Mr. Warington deserves our thanks for his work, both from its 

 showing the interdependence of branches of science and from its 

 being an important addition to the scientific knowledge of our 

 county. 



In conclusion, let me say that my remarks are meant to be 

 suggestive, not dogmatic. We have yet much to learn on the 

 subject of Chalk water, and it is to be learnt, not by work in one 

 groove only, geologic or otherwise, but by joint work in various 

 di\-isions of science. It is pre-eminently a subject for a Society 

 such as ours, being general in scope but needing local treatment. 

 We have already published some papers on the subject, and if this 

 Address leads to further records being undertaken and brought 

 before us, it will not have been useless. 



