BENEATH THE LONDON CLAY. 161 



There is one other fact which seems to point to a similar con- 

 clusion. If the intermingling of sand and chalk waters is a very 

 local phenomenon ; supposing the supply of the sand-water not to 

 be practically unlimited, it might happen that by continued pump- 

 ing the sand-water would show signs of exhaustion, and its effect 

 on the chalk water be proportionately diminished, so that possibly 

 after a time its effect might be inappreciable. Now, the Harrow 

 water has been examined at different times, though, unfortunately, 

 we have no fu// mmera/ analysis of it at the earlier dates, but this 

 is the result : — 



In 1868, the total solid contents were 1044, and the hardness 

 48"5. In 1870 these were reduced to 1009 and 44*4 respectively; 

 in 1873 to 981 and 40*8 ; and in 1883 to 884 and 38-5.* 



This appears to show a progressive improvement in the water 

 from the Harrow wells, and it would have been interesting, from a 

 scientific point of view, to follow up these observations from year 

 to year in order to see whether the change continued. Unfortu- 

 nately for science, whatever the advantage to the inhabitants of 

 Harrow from an economic point of view, this is no longer possible, 

 for our pumps stand idle, and Harrow is now supplied with water 

 by the Colne Valley Company, drawn from wells in the open 

 chalk at Bushey. 



Here, then, as far as my information extends, is another 

 unsolved problem, which I commend to any members of this 

 society who may have been interested in the facts I have brought 

 before you this evening. I venture to hope that by the gradual 

 accumulation of suitable observations, a satisfactory explanation 

 of the anomalies to which I have called your attention (I fear with 

 too great demands on your patience) may be found. I would 

 merely suggest that possibly the solution of the anomalous charac- 

 ter of the Harrow water may be found to be connected with the 

 fact that at Pinner, about two miles to the north-west, the Wool- 

 wich beds rise up to the surface. 



I will only add that as, though water is naturally so/i, the influ- 

 ence of Harrow Hills appears to be to make it excessively /lard, so 



* Or possibly to 34'3, if calculated in the same way as at the previous dates. 

 Vol. VL m 



