Page:Popular Science Monthly Volume 72.djvu/240

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POPULAR SCIENCE MONTHLY
The Same viewed from the Outer Edge of the second Ledge of the Sea-footing.

just east of the pagoda, and yet now and again the bore swelled up to the wall as it sped along. The southern end, meeting an incline of sand which rises only nineteen feet in a mile and a half, trailed away in a line of very deliberate breakers, which ceased half a mile to the rear of the bore or where it had passed three minutes before.

A second smaller bore followed directly after the first in the form of a group of secondary rollers on top of the first body of water, and several hundred yards in the rear of the crest behind which for many tens of feet the rushing water was churned into foam by the turmoil. These secondary rollers leaped up from time to time as if struck by some unseen force and disappeared in heavy clouds of spray. These breakers on the top of the flood were sometimes twenty to thirty feet above the level of the river in front of the bore, while the conflict in progress on the river-bed itself was clearly evidenced by the quantities of mud, sand and even large gravel which were seen to be mingled with the surging waters.

The river filled up to the level of the bore soon after it had passed, but not evenly.

A quarter of an hour after the bore had passed Haining, the water had risen thirteen feet; after two hours it had risen eighteen feet; and a high-water mark of nineteen feet was attained at 4:45, or after three hours of flood tide. At this time the stream commenced to run out swiftly. At 6:45 p. m. mean level was reached and at 9:45 it was practically low water again, though the out-going stream continued