THE SHALLOW AND DEEP WELL WATERS OF ESSEX. 29
various Villages and Hamlets in the Chelmsford and Maldon
Rural Sanitary Districts," which contained the results of the
analyses of 400 samples of drinking water derived from the most
varied sources—rain-water tanks, ponds, ditches, streams, springs,
shallow wells in Boulder clay and in various kinds of gravel, and
deep or artesian wells, sunk through the London Clay to the sands
and chalk beneath.
In the introduction it was affirmed that the waters yielded by
gravels of different origin differed much in character. A copy of
this report reached the hands of our esteemed member, Mr. W.
Whitaker, F.R.S., and he wrote me saying that he had noticed
this remark, and that "it would be interesting to study such
differences, if they existed." He adds, "There may possibly be
some difference between gravel-water and sand-water, of whatever
age the deposits may be, and you might be on the look out for
this."
Tables of analyses of typical waters, or of waters which for some
other reason are interesting, have been prepared and are appended
to this paper.1 Out of the hundreds of analyses of shallow well-
waters I have made, there are few which are of any use for our
purpose. In many instances the subsoil water supplying the wells
has become so contaminated with the filth deposited on the surface
of the ground, or in defective cesspits, cesspools, and bumbies, that
the character of the water has become entirely altered. For examples
I would refer you to my Report on the Writtle Water Supply, a few
copies of which are upon the table for distribution. Writtle village
stands upon a patch of Glacial gravel. At the edge there are nume-
rous springs. The analyses of five of these are given as being
typical of what the water from this gravel patch should be. We
may compare these with the analyses of the water from the village
wells.
Out of the forty-eight shallow well waters only one or two bear
any close resemblance to the spring waters; all the others are more
1 See appendix of Tables of Analyses, inserted in the present number.—Ed.