A correspondent in the last number ol " Hunt's Merchants Magazine," gives a very interesting account of phenomena connected with Lake Ontario. It has been long known that this lake is subject to frequent risings and fallings of the waters, and by many it has been supposed that such changes were re gular. This, by long observation, has been found to be incorrect; the risings and fallings of the waters are not regular, but oftentimes sudden and produce wonderful effects. At Port Hope, Coborg, Graton, and Colbourne, the water recedes suddenly and leaves the harbor bare, and then returns with a violent roar and invades the land. This portion of Lake Ontario is subject to great submarine convulsions, and sometimes the waters ebb and flow every ten rr.inuttxs. A convulsion of the Lake took place in September 1845, which gave birth to a terrific thunder storm, and was accompanied by a severe tornado. Another took place on the 5th July, 1850, which created a terrific water spout, which was broken by a bolt of electricity, that appeared to have come from the bottom of the Lake. Part of the water spout in a dark cloud passed over to the land depositing its waters at the heads of the Canada Creek, which raised the said Creek so suddenly as to carry away the railroad bridge of the Schenectady and Utica Railroad, before the trains could be informed of the event. The waters of Lake Ontario have been known to fall iourteen inches in thirty-six hours, and these waters could not have been carried away in that short period by the river St. Lawrence. The Lake is underlaid with fossiliferous limestone, from the north shore in Canada, to the south shore, and it is not long since Watertown and Lowville were severely shaken by an earthquake; these places being built on the same limestone strata. This section ol the Lake sometimes produces fearful lightning storms, one of which visited 1S51, while there were three feet of snow on the ground. These facts seern to corroborate the views expressed on page 264, this Vol., Sci. Am., by Mr. Drummond, respecting some earthquakes which had taken place in North Britain. " If some convulsion of nature were to take place so as to tumble down the falls ot Niagara," says the author ol the article referred to,li Lake Erie would become a river." Such a convulsion would need to open up a channel through the rock above the present falls a few miles long; some suppose that this was done once before, and that the Falls were down at Lewiston. There is a mystery connected with the rise and fall of the waters of Lake Ontario, which cannot be accounted for by continued rains or the melting of snows.