. The earth and its inhabitants ... Geography. THE REGION OF LAKES. 82^ 730 west of the Valaam group ; but the mean depth is estimated at no more than 300 feet, which would give the whole basin a volume about nineteen times greater than that of Lake Geneva. The amount, however, varies considerably with the seasons and years, observations continued for fourteen years showing a difference of no less than 7 feet between low water and the floods. The monks of Valaam assert, on the strength of an otherwise unauthenticated tradition, that the general level rises and falls alternately from century to
. The earth and its inhabitants ... Geography. THE REGION OF LAKES. 82^ 730 west of the Valaam group ; but the mean depth is estimated at no more than 300 feet, which would give the whole basin a volume about nineteen times greater than that of Lake Geneva. The amount, however, varies considerably with the seasons and years, observations continued for fourteen years showing a difference of no less than 7 feet between low water and the floods. The monks of Valaam assert, on the strength of an otherwise unauthenticated tradition, that the general level rises and falls alternately from century to century. Notwithstanding the muddy contributions of such rivers as the Volkhov, the water of Ladoga is generally so pure that the smallest objects lying at the bottom are perfectly visible in depths of 14 or 16 feet. It is always very cold, Fig. 174.—; and Asar about Lake Sog. Scale 1 : 1,200, Heic-ht in Feet es^ i: 1(ju to aao. &« to 4U0. 41)0 to efivO. eeo to 820. 820 to 1 \ StriSR. \ Asar. =_ 10 Miles. except perhaps in August, when the temperature about the surface may occa- sionally rise to 50° or 05° Fahr. But even in July it is scarcely safe to drink it, and at the thaw towards the end of May the surface water is about 2° above freezing point. The temperature between the surface and lower depths usually varies less than 1°, the latter being somewhat higher in winter, when the lake is ice-bound. Lying somewhat south and to the west of Onega, it remains frozen for a shorter period, usually about one hundred and twenty days, from the middle of December. Some of the central parts occasionally remain open throughout the year, whereas Onega is nearly always completely ice-bound for one hundred and fifty-six days. But sufficient air is still retained in the lower depths of these basins to keep their fauna alive during the winter season. Both of them are inhabited by a seal. Please note that these images are extracted from scanned page images that may hav
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Keywords: ., bookcentury1800, bookdecade18, booksubjectgeography, bookyear1883
