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II. ON RECENT EXTRAORDINARY OSCILLA- 
TIONS OF THE WATERS IN LAKE ONTARIO 
AND ON THE 
SEA-SHORES OF PERU, AUSTRALIA, 
DEVONSHIRE, CORNWALL, &c. 
By RicHARD EDMONDs. 
Yk HESE tide-like alternating currents, which resemble in 
all respects those observed on the shores of this and 
other countries on the days of the two great earth- 
quakes of 1755 and 1761, commence generally, if not always, 
with an efflux, and occupy from five to ten minutes in ebbing, 
and about the same time in flowing, the ebb and flow and 
the imperceptible interval between them never exceeding 
twenty minutes. Those on the 5th of July, 1843, were 
observed between the hours of If a.m. and 5 p.m. in 
Plymouth, Falmouth, Mountsbay, the Scilly Isles, Bristol, 
and on the eastern coast of Scotland at North Berwick and 
Arbroath. ‘Those of the 29th of September, 1869, occurred 
on the northern as well as on the southern coasts of Devon- 
shire and Cornwall, and at the Scilly Isles. Of these and 
all the intermediate ones of importance in these two counties 
I have written full descriptions, including all meteorological 
particulars.* 
These currents, when running in and out of piers or 
narrow channels, often drive vessels from their moorings, 
and dash them against one another. But when they are 
moving up and down a wide open beach, the motion is so 
quiet and tide-like that they would not be perceived unless 
they were watched for some time. This was amusingly 
exemplified at Penzance, when, during such an oscillation, 
some children who had been long enough on the beach to 
discover it made a play of their discovery, by inducing other 
children who had not observed it to go out on some rocks 
left dry by an efflux, where they were soon surrounded, and 
for many minutes in a great fright lest they should be 
drowned. 
Such is the nature of these extraordinary oscillations 
after the first efflux, whether on sea-shores or on the shores of 
lakes. The first efflux is well illustrated by that in Lake 
* See “ Literary Gazette” of June, 1843; The ‘‘ Edinburgh New Philosophical 
Journal,” 1845, and following years until it merged into the * Quarterly Journal of 
Science ;” and the “Philosophical Magazine”’ for January, 1866, and January, 
1869. 
