264 NOTES—ORIGINAL AND SELECTED.
Interesting Phenomenon Observed in Epping Forest.
—On a bright morning following a wet night in the early part
of last spring, I was strolling in the Forest near "Cook's Folly,"
and, on approaching Forest Road, was arrested by a curious sound
resembling that of water boiling. At the time, I was walking
along a well-trodden path in a small glade, picking my way
carefully amongst the surface puddles and small stretches of
shallow water resulting from recent rain, the ground at that
part being a yellow clay slightly mixed with gravel.
At first, I could not locate the sound ; but, proceeding a
few yards further, I came to a slightly-lower stretch of clay.
There I observed that the surface puddles were speckled
with bubbles, which appeared to be rising rapidly from below.
On examination, I found that there were tiny perforations
in the surface of the clay, from which air was apparently issuing,
thus giving rise to a stream of tiny bubbles from each vent
as it came up through the water, the noise made by the multitude
of bursting bubbles combining to produce the sound which
had arrested my attention.
I had never met with a similar occurrence before, and could
only conjecture that, owing to a rather dry spell before the rain,
the ground had dried some little way down ; that the sudden
rain had imprisoned the air beneath the surface ; and that
the air was gradually making its way up as the water percolated
down. One meets, of course, with isolated cases of bubbles
coming from the ground, especially in marshy districts, but
it is not often, I think, that a stretch of solid ground some
20 feet by 4 or 5 feet exhibits it on such a scale as to arrest
the attention of the passer-by.
If my explanation is not deemed sufficient, I shall be glad
to hear of a better.—C. Nicholson, Hale End, Chingford.
Pied Flycatcher in Essex.—On the afternoon of
Wednesday, 8th May, I shot a Pied Flycatcher close to this
house and am having it stuffed by Mr. Pettitt, of Colchester.
Mr. Miller Christy's Birds of Essex shows that, in this county,
the bird occurs only as a scarce and irregular passing
migrant, generally early in May or late in August.—James
Campbell, Prested Hall, nr. Kelvedon, Essex.