22 
WATER-LEVEL AT BARLEY, HERTS. 
It will be seen from the chart that the mean time of highest 
level is April 1st, there having been, after the autumn and winter 
rains, a sharp rise from the lowest point (November 1st). From 
April 1st to May 1st there is a slight fall, again in the following 
month a rise, and from June 1st a steady fall to November 1st. 
Taken generally, the movement of the water is a rise for five months 
(November, December, January, February, and March), and a fall 
for the remaining seven months, through the summer and autumn. 
My own daily observations at Odsey, commencing at the end of 
1878, have hardly, as yet, extended through a sufficient number 
of consecutive years to be worth publication; but, for the sake of 
comparison with the Barley record, I have worked out the mean 
monthly level for Odsey, and have represented it on the chart by a 
second line. This line shows that the same regular rise and fall 
occurs in the Odsey well, except that the mean highest level of 
water is one month earlier than at Barley, and that the summer and 
autumnal fall is unbroken by any upward movement. 
A detailed examination of the figures in the table, or of a chart 
representing them, shows great variations from the mean level in 
years of and those following excessive and small rainfalls, and it 
will be seen that the extreme variation in level has been as much 
as 78 feet—between 2 feet (January, 1864) and 80 feet (August, 
1879). The greatest difference in any one year was in 1869—in 
January 20 feet, and in April 57 feet, a rise of 37 feet; and the 
least in 1871—in January 6 feet, and in June 18 feet, a rise of only 
12 feet. The mean level for the year 1879 was 70 feet, and that 
for 1864 only 11^ feet; 1879 being also the year of heaviest rainfall 
for the period (30-00 inches), and 1864 being that of the smallest 
rainfall (16*67 inches), preceded by a small rainfall (17*87 inches) 
in 1863. In these comparisons the two imperfect years 1883 and 
1884 are omitted. 
At some future time, and in connection possibly with the 
publication of results of observations in the Odsey well, I hope to 
discuss the variations of water-level in the Chalk of North Herts 
more fully; but, in the mean time, so valuable a record as that for 
Barley should not, I think, remain unpublished. 
Possibly the publication of this record in our ‘ Transactions ’ may 
induce members of the Society who have deep wells in the Chalk 
to set on foot a regular registration of the depth of water in them, 
either at monthly or shorter intervals. Any systematic observations 
of this character cannot but be of great value. 
li'.KjA 
