244 On the Rain and Drainage - Waters at Rothamsted. 
rainfall can be ascertained to ij^qq of an inch. A sketcli of this 
rain-gauge will be found in Fig. 1 (p. 243). Its use commenced 
in July 1873, and has been continued down to the present time. 
Besides the two large gauges just described, an ordinary 
rain-gauge, consisting of a circular copper funnel 5 inches in 
diameter, delivering into a bottle enclosed in a metal cylinder, 
has been continuously employed, and its readings recorded. 
This gauge was at first placed by the side of the first large 
gauge, and at the same elevation above the ground ; it has since 
been moved to the side of the second large gauge, and brought 
to its level. 
2. Tlie Amount of the Rainfall. — The total rainfall recorded 
by the first and second large gauges during the first year of 
their comparison was practically identical, the old gauge show- 
ing a rainfall of 22*361 inches, and the new gauge a rainfall of 
22'363 inches. A considerable difference afterwards appeared 
between them, arising apparently from leakage in the old gauge, 
which had also altered somewhat in form from the warping of 
the wooden framework. The use of the old gauge was therefore 
finally discontinued. 
The small gauge has shown, on an average, a distinctly 
smaller rainfall than the large gauges. Taking a mean of 
28 years (1853-80), the large and small gauges compare as 
follows : — 
Table I. — Comparison of the Large and Small Eain Gauges 
(mean of 28 Years). 
Mean Monthly Eahifall. 
Deficiency of Small Gauge. 
Large gauges. 
Small gauge. 
Actual. 
Per cent. 
Inches. 
Inches. 
Inches. 
Inches. 
2-590 
2-263 
0-327 
12-6 
1-728 
1-508 
0-220 
12-7 
1-693 
1-399 
0-294 
17-4 
2-008 
1-803 
0-205 
10-2 
2-329 
2 149 
0-180 
7-7 
2-451 
2-272 
0-179 
7-S 
July 
2-704 
2-533 
0-171 
6-3 
2-643 
2-440 
0-203 
7-7 
2-638 
2-403 
0-235 
8-9 
3-089 
2-784 
0-305 
9-9 
2-345 
2-113 
0-232 
9-9 
2-084 
1-861 
0-223 
10-7 
Total for Year . . 
28-302 
25-528 
2-774 
9-8 
It is seen that the small gauge agrees best with the large 
gauges in the summer months, and that on either side of July 
the difference between them gradually increases. The largest 
