III. 
A RECORD OF WATER-LEVEL IN A DEEP CHALK WELL AT 
BARLEY, HERTS, 1864-1886. 
By H. George Fordham, F.G.S. 
Read at Watford , Z\st January, 1888. 
PLATE I. 
I hate recently obtained a copy of the record of a series of 
monthly observations of the level of the water in a deep well 
sunk in the Middle Chalk on its outcrop on the northern margin 
of the London Basin, in the viilage of Barley, about three miles 
south-east of Boyston. 
These observations have (with a few trifling breaks) been regularly 
made for nearly 23 years, from January, 1864, to October, 1886. 
They have come to an end through the illness and death of the 
observer, Mr. John Pearce, who died in May, 1887, at the advanced 
age of 84. 
Becords of the variations of underground water-level have as 
yet hardly received the attention they deserve; and although, 
within the last few years, observers have multiplied, and a certain 
amount of public interest in the subject of our underground water- 
supplies has sprung up, there remains a large field for research in 
this very practical branch of scientific observation. 
A satisfactory knowledge of the amount and variation of the 
stores in our subterranean water-reservoirs, and of the relation of 
the supply to the rainfall as measured at the surface, can only be 
obtained by means of a series of observations spread over wide 
areas, and extending through a considerable period of time, and 
consequently such a regular and lengthy record as that kept by 
Mr. Pearce is of great interest and value. 
It seems desirable that the record should be printed in the form 
in which it was kept by Mr. Pearce, and I have accordingly 
prepared the Table on page 21, giving his figures, as arranged by 
him, and adding only (1) the last column, showing the mean 
monthly level of the water for the 23 years; (2) a line at the 
bottom of the table, giving the mean height for each year; and (3) a 
statement of the annual rainfall at Boyston, 1863 to 1886, kindly 
furnished to me by Mr. Hale "Wortham. At the head of the table 
are notes of the position of the well, its height above the sea- 
level, and its depth. 
I have also prepared a chart showing, for each year, the curve 
representing the alteration of the water-level from month to month; 
but, unless constructed on a large scale, such a chart for so many as 
23 years becomes somewhat confused, and I therefore only repre¬ 
sent in this way the mean monthly level, as given in figures in the 
last column in the table. In this the year begins on April 1st, at 
the commencement of the summer half-year, the date most con¬ 
venient for the purpose. 
