Indian chieftain. [volume] (Vinita, Indian Territory [Okla.]) 1882-1902, 1902-03-13
EARrHwoRMs AND STONES.
Remarkable Effect of subterranean
BurrowinRs OF the squirmers
.Npon large Bowldera.

The following account is given by
G. DAWSON, in knowledge, of the sink
Ing Of large stones by carthworms'
borrowings. Horace Darwin COM
menced an experiment 20 years ago.
= circular stone about IS inches In d.
ameter and "a inches thick. and
weighing about A. pounds was laid
upon the ground in q level field near
Mr.. Dnrwin's house at Down, which
had probably been pasture for more
than so years, and under a large Span
ish chestnut tree. A hole was made
through its center and was lined with
a brass cylinder containing on the top
three horizontal projecting pieces
loaded into the upper surface Of the
stone. In each Of these pieces radial
N-shaped groove was cut. To obtain
liked point from which the displace-
ments OF the stone were to be meas
ured, two rods, one OF copper and the
other Of iron, and each SO of an incn
in diameter, were driven side by side
into the ground TO the depth Of about
s1 feet, and the ends were cut on so
that they stood az first about Tire.
inches above the ground, or not quite
an inch above the upper surface OF
the stone. which was placed with the
rods projecting through the central
hole. Movements OF the stone were
produced by other agencies than the
burrowing Of earth worms. Some,
but an unknown. displacement may
have been caused by the growth of
the roots Of the chestnut tree. under
which the stone lay. But this, II II oc-
CURED, must have been far less than
that due TO frost and changes In the
dampness OF the ground. The stone,
indeed, was found 10 be IN q state-of
continual vertical oscillation. When
the soil was damp from recent rain,
one or two cans Of water poured on
the ground near the stone made IL
rise one-iiftieth Of an inch In about
seven hours. During a severe frost
in the beginning OF 1879. the stone rose
three-tenths Of an inch. and, during
the thaw which followed a slight frost
a little later in the same year. IL fell
nearly one-tenth OF an inch In less
than five hours, even though the
NA0hAAN nNANM wis NlNIN nara.
Until the end Of 1856. the position of
the stone was usually measured each
winter and summer. and during the
next ten years in the summer only.
The curve obtained from the summer
measurements Is more irregular than
from those made I'm winter. probably
on account OF the greater variation in
the dampness Of the soil IN summer.
During the last nine years in which
the experiment was made (ss7-1s96)
the total descent, given bv summer
measurements, was less than one
eighth Of an inch. II Is difficult TO !
account completely tor this very slow
rate, but, during part OF the time the |
rainfall was certainly above the av-
erage. In the earlier half of the
interval, however. the rate OF descent |
was much greater. though this may
have been partly due to the decaying |
OF the grass, for the stone was at
hrst placed directly on the turf. TAX
ing the winter readings. Horace Oar,
win found that the stone sank seven
tepths of an inch in the eight wears
from ISIS to 15sG, or at the rate of |
seVen-eigh'hs of an inch in ten years.
This, as we might expect, il much less
than the rate at which worms cover
up small pebbles, but II is about twice |
as great as that at which the large |
stone examined by bis father sank |
into the ground.