The Earthquake in Relation to Geological Structure. 161
certain fluctuations, been maintained since April 22nd, a
reading taken on December 15th giving a height of 42
inches.58
This effect of an earthquake shock in raising the level of
subterranean water has not often been recorded, although
such results must have frequently been observed in earth-
quake countries. A somewhat remarkable instance of the
kind was caused by an earthquake which occurred in Con-
necticut on Aug. 10th, 1884 :—
" At Rocky Glen, where all attempts to obtain water by
digging wells had always failed, there has been an abundance
of water since the occurrence of the earthquake. Previous to
that all water used in the houses and greenhouses was
brought from a long distance, necessitating much labour and
expense. The stream has continued unabated in quantity
and is of excellent quality."59
Numerous conjectures as to the cause of the rise of the
water in these wells have been advanced, such as the collapse
of subterranean reservoirs, general alteration in the level of
the land, &c, but none of these appear to us to bear the test
of critical examination. We are disposed to accept the
explanation first offered by Mr. 0. E. De Rance, P.G.S.,60
Secretary to the Underground Water Committee of the
British Association, viz., that the shock caused a widening of
the fissures through which the water circulates in its course
down to the lower chalk beds, and thus, by an increased flow,
58 Mr. Sharpe has been good enough to supply me with a graphical
representation of these measurements on ruled paper, which shows the
sudden rise between April 21st and 28th in a very striking manner.
[According to the latest report from Mr. Sharpe (Aug. 11th, 1885), the
water here, as at Colchester, appears to be gradually falling, although it is
still considerably above its old level. The readings (monthly) from Aug.,
1884 to the present time are 54, 521/2, 42, 421/2, 42, 42, 44, 411/2, 46, 441/2, 40,
381/2, and 391/2 inches. Some of this fall is probably due to the small
amount of rainfall during the last few months.]
59 From the 'Danbury News'; recorded in the 'Monthly Weather
Review' for Oct., 1884, published by the U. S. Signal Office ; forwarded
by Mr. G. J. Symons, F.E.S.
60 ' Nature,' May 8th, 1884, p. 31.
M