﻿Wellingt07i Philosophical Society. 375 



The deductions drawn from these results are as follows : — 



(1.) Though the opening of the river from ice now happens a little later 

 than in former times, the high water begins earlier, so that the time elapsing 

 between the opening and the beginning of high water is diminished from 

 thirty-nine to twenty-four days, and the highest flood now arrives seventy-six 

 days after the opening instead of eighty -six. 



(2.) The period of high water is becoming longer, and the height of the 

 water generally a little increasing. In the continental climate of Eastern and 

 Central Russia the earth is covered with snow for four or five months in the 

 year, and the rivers are frozen for nearly the same time. Even in Astracan, 

 in 46° 40' north latitude, the river is frozen for nearly 100 days, and the 

 middle temperatxire of winter is 21 '7° Fahr.. The rivers rise in spring, when 

 the snow is melting. From Astracan to 51° north latitude, the land is generally 

 a steppe and unaltered, but to the north the basin of the Wolga was covered 

 with beautiful forests. Kow, with the settling and cultivation, with the 

 enormous increase of factories, and steam navigation on the rivers, the forest 

 has been devastated to a great degree. In wooded countries the snow lies 

 longer in spring, as it is protected by the trees — in some cases the difference 

 may be a month. It melts slowly, and does not cause the disastrous floods 

 which occur in a bare country. It will be seen also that the end of the flood 

 arrives later and later. This gives an indirect answer to the q^uestion whether 

 the quantity of rain has diminished or not after the felling of the wood. The 

 table leads the author to think that there has been no diminution, but it m.ust 

 be remarked that in a wooded country more of the rain is retained by the 

 roots, mosses, and fallen leaves, and, in consequence, less of it is free to reach 

 the mouth of a river. In an open country most of the water which falls 

 during the rains of summer runs to the rivers, destroying the arable land, so 

 that even a greater quantity of rain may profit the surrotmding country very 

 little, and the inhabitants may be in the right when complaining of drought, 

 if the land is cleared of forests, as seems to be the case in the basin of the 

 Wolga. The complaints of the agriculturists are general, and the observations 

 on rainfall have not been of sufficient duration to decide the question. 



The position of the Wolga basin affords indirect evidence on this point, as 

 its rainfall is gathered into an inland sea — the Caspian — the level of which has 

 greatly risen since 1866, and as most of its waters are poured in by the Wolga, 

 we must infer that this river now collects more water than it did formerly. 



Dr. Hector said that the paper just read, the manuscript of which had 

 been sent to him by the leax^ned author, related so a subject of peculiar interest 

 to New Zealand meteorologists, as the effect on the climate produced by the 

 clearing of forests can be observed in this country without the complications 

 due to distant influences which affect continental climates. 



