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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, 1 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. 
1 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 tiie 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, C king ford. 
Pied Flycatcher in Essex.— On the afternoon of 
W ednesday, 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. 
