FROM TIIE CHALK OF HERTFORDSHIRE. 
153 
that a smaller number of stones can now be worked than formerly, 
and many millers are obliged to put down steam-engines. Even 
within the last ten years, the Hon. A. H. Holland-Hibbert informs 
me, the level of the water in the Colne at Munden has gradually 
fallen to the extent of four or five inches. Watercress-growers are 
complaining of shortness of water, and it seems as if one of the 
most important industries of Hertfordshire, if not the most impor¬ 
tant, were seriously threatened with extinction. Wells are running 
dry, and have to be deepened so that they may continue to yield 
a supply. This has been the case at the Watford and also at the 
Berkhamsted waterworks; at the St. Albans waterworks, near 
Bernard’s Heath, the pumps, at one time working under water, 
have had to be carried down some distance to enable them to 
draw water at all, and a new pumping-station has been erected in 
the valley, close to the Biver Yer, and is now to be extended by an 
additional bore-hole, by which means an increased amount of water 
will be, indirectly, drawn from the river; and at the Ware water¬ 
works the water-level has lowered progressively about a foot a year 
for the last 18 or 20 years. 
It may be urged that increased drainage may have had some effect 
in carrying the water more rapidly off the land, and so permitting 
less to percolate, but that would augment the flow of our rivers for 
the time, and of this we have no evidence so far as I am aware. It 
may very likely, on the other hand, have had the contrary effect, 
for we do not underdrain the chalk, where percolation is compara¬ 
tively rapid, but only stiff wet land, where there is scarcely any 
percolation, and on it the drainage may, by removing water from 
the surface where it is subject to rapid evaporation, increase the 
amount which percolates. The main cause of the permanent reduc¬ 
tion in our water-level in Hertfordshire in recent years must be 
the abstraction of water by pumping and the removal of that water 
to a distance for the supply of London and the district between 
Watford and London. The water pumped up for our own use will 
add its quota, but only in the immediate neighbourhood of the wells 
and borings, for practically all of it is returned into the chalk or 
sent into our rivers after we have done with it. 
It may be objected that, after all, this process of depletion must 
be very slow, for we have a vast reservoir to draw from. This 
objection admits of an easy and complete refutation. 
Hertfordshire has an area of 633 square miles, about half of 
which is occupied by permeable strata. The greater part of this 
area is in the catchment-basin of the Thames, a small portion in 
the north (about 75 square miles) being in that of the Great Ouse. 
Of that in the Thames, a very small portion (about 10 square miles) 
is in the catchment-basin of the Thame in the north-west, and 
another still smaller portion (about 5 square miles) is in that of the 
Brent in the south, the bulk, about 543 square miles, being in the 
catchment-basins of the Colne and Lea. On the east the Lea and 
its tributaries drain a considerable portion of Essex; on the west 
the Colne and its tributaries drain a much smaller portion of Bucks. 
