1854.] 



ON THE PERIODICAL RISE AND FALL OF THE LAKES. 



301 



one-tliird of that which was the minimum of several preceding 

 years. 



" Ontario, from the reports of professional men, has varied 

 not less than eight feet; and Erie about five. Huron and Su- 

 perior, being comparatively unknown, no dates are afforded to 

 judge of them. But what vast atmospheric agencies must have 

 been at work when such wonderful results on the smaller Lakes 

 have been made evident !" 



"What a useful thing," further observes Sir Richard, it would 

 have been, if scientific navigators, or resident observers had 

 registered the rise and/all of the Lakes in the years since Canada 

 came into our possession," 



Among other unconnected notes I find also some judicious 

 remarks, extracted from McGregor's British America;* but from 

 these I must be content to quote only the following, as referring 

 to a collateral philosophical question of deep interest which may 

 perhaps be touched on in the sequel: namely, the possibility of 

 there being a subterraneous outlet to some of the great Lakes — 

 a hypothesis which I have long been disposed to regard as not 

 altogether irreconcilable with the geological formation of the 



.... DO 



basins ot the middle and lower lakes, though perhaps not so with 

 the structure of the Lake Superior regions; it being doubted 

 whether, notwithstanding the great annual evaporation, the volume 

 of water discharged by Lake Erie does sufficiently account for 

 the vast united supply received by it from the immense triple 

 resources of Lakes Superior, Michigan, and Huron. 



" As the temperature of the climate in America depends 

 chiefly on the winds, the formation of that continent is evidently 

 the cause of the frosts being more intense than in countries in 

 parallel latitudes in Europe; a consequence arising principally 

 from the much greater breadth of America towards the poles. 

 Winds change their character in America. North-east winds, 

 which are cold and dry in Europe, are wet and truly disagreeable 

 in America. North-west winds are, on the contrary, cold and 

 dry, and are frequent during winter in America, much about the 

 same period that north-easterly winds prevail in Europe. One 

 great, if not the principal, cause of cold in America is the direc- 

 tion of the mountainous ranges and basins of country which 

 conduct or influence the course of the winds. While the sun is 

 to the south of the equator, the winds less under solar influence 

 prevail from the north-west, following, however, the great features 

 of the continent. The winds blowing over the vast regions of 

 the north are always piercing and intensely cold. The return of 

 the sun, again, by the diffusion of heat, agitates the atmosphere 

 and alters the winds, which blow from a contrary direction, till 

 the equilibrium is produced. This, however, does not appear to 

 require much time, as no wind blows scarcely forty hours to- 

 gether from any one point. 



" The comparative depths of the Lakes forms another extraor- 

 dinary subject of enquiry. The bottom of Lake Ontario, which 

 is 452 feet deep, is as low as most parts of the Gulf of St. Law- 

 rence, while Lake Erie is only 60 or 70 feet deep; but the 

 bottoms of Lakes Huron, f Michigan, and Superior, are all, from 

 their vast depth, although their surface is so much higher, on a 

 level with the bottom of Lake Ontario. This is certainly not 

 impossible; nor does the discharge through the Detroit river — - 



* See McGregor's British America, vol. 1, pp. 131 to 133. 



j- As an instance of our ignorance of the true depth of some of our 

 Lakes, it is proper to note here that that of Lake Huron has, after all, 

 been lately ascertained by the American Coast Survey to be not more 

 than 420 instead of 8C0 feet !— R. L. 



2 



allowing for the full probable portion carried off by evaporation 

 — appear by any means equal to the quantity of water which the 

 three upper great Lakes may be considered to receive. All the 

 Lakes are estimated to cover 43,040,000 acres. The great Lakes 

 occasionally rise above their usual level from three to five feet. 

 These overflowings are not annual nor regular. They have oc- 

 curred about once in seven years, and are probably the effect of 

 more rain and less evaporation during the seasons in which they 

 take place. Sir George Mackenzie observed occasional over- 

 flowings of two to three feet in the Lakes north-west of Lake 

 Superior; so that they are not peculiar to the Lakes of the St. 

 Lawrence.'' 



Having at length nearly exhausted my miscellaneous quota- 

 tions and notes, I propose concluding that main branch of my 

 task with the following appropriate remark, derived from a note 

 at page 133 of the 1st volume of Talbot's Canada, as not only 

 bearing on the now generally admitted influence of prevailing- 

 winds on the temporary fluctuations in the level of the Lakes, 

 but also as adverting to the almost equally demonstrable fact, 

 that the singular severity of our Canadian winters, and more 

 particularly those of Lower Canada, compared with European 

 countries in the same parallels of latitude, is altogether unin- 

 fluenced by the vast extent of our Lakes; on which subjects 

 the author referred to, quoting an American author, states as 

 follows :- — 



'' Professor Dwight has proved that the height of the river 

 (Niagara) both above and below the Falls, depends on the quarter 

 from which the wind blows. Lake Erie, he says, is regularly 

 raised at the eastern end, where the Fall commences, by every 

 wind blowing between north-west and south-west. A strong 

 westerly wind elevates its surface six feet above its ordinary 

 level. The rivers must, of course, be proportionally elevated ; 

 and at the outlet must, when such a wind blows, be six feet 

 higher than the usual water mark. . . On the contrary, 

 when the wind blows from the north-east (the only easterly wind 

 which in this region is of any importance), the waters of Lake Erie 

 must recede of course, and fall considerably below their usual 

 level, and the river be necessarily lower than at any other time." 



The same author, in another part of his work (pp. 339 to 342), 

 remarks as follows, with regard to the climate of Canada differ- 

 ing from that of European countries in a similar latitude: — 



" The cause of this phenomenon appears to have eluded the 

 most diligent and profound research. Many writers attribute 

 the severity of the winter to the astonishing prevalence of north- 

 west winds, and the amazing extent of the Lakes. That the se- 

 verity of the weather in winter cannot with any propriety be at- 

 tributed to the influence of the Lakes will appear evident to 

 every man who reflects that the shores of those great inland seas 

 enjoy a much milder climate than any other part of the country 

 in the same parallels of latitude, however remotely situated from 

 them. Fruit trees thrive well and bring their fruits to great per- 

 fection along the north-west extremity of Lake Ontario, in lat. 

 43 deg 30 min., and along the north shore of Lake Erie; and 

 yet at 35 miles from the latter place, and in lat. 42 deg. 20 min., 

 this fruit cannot be cultivated ; and I have also seen snow three 

 feet in depth a degree south of Lake Ontario, while at the 

 same time it did not exceed six inches in the immediate vicinity 

 of that Lake.'"J; 



J See the letter introductory to my late paper on the establishment 

 of a system of meteorological observations ; and also the note at the 

 foot of page 293 of this Journal. — R. L. 



