1826.) Notices regarding the Climate of Russia. 305 
feony this Cause that the air is cooler ina forest than in another merely shaded 
i e; and in a church or other large building with massive,wallsy passing 
feep in the earth, than in a small house. In several countvies,,.were the 
sie very hot, the inhabitants carefully shut the doors wnd.windows of 
ir houses during the middle part of the day; and it may be observeds ge- 
nerall , that in ‘o dipary houses thus closed the temperature of “the ait-ds 
Several’ degreze ioe that_of the exterior atmosphere, where this.is. perfects 
ieee ed. Even after several wecks of continued. hot weather, the walls, of 
jouse will be found several. degrees colder than the mean temperature of 
> air during that period ;_.and_ yery often colder than the air has been at its 
lowest temperature, This shows that the walls of the house are colder. than 
the air, not merely because they caunot, regarded abstractedly, become warmed 
pA sun as readily as the air, but also because, from their communication 
ith the earth, they suffer a constant abstraction of heat. 
. There is another thing that contributes, but not in a considerable degree, to 
render islands in the great ocean less cold in winter than plains remote from 
mountains about the interior of large continents, which is, that the atmos- 
phere of the former is generally less clear than that of the latter region. «Lhe 
extremes of cold, in respect to any certain region, never cxist when the atmos- 
phere is clouded ; and this arises, as it appears we must infer, from the clouds 
reflecting the heat radiated from the surface of the earth. With the extremes 
of cold there is always a clear deep blue sky; and the intensity of the-blue 
tint in Russia, with such cold, exceeds what is observable even -in Italy at 
any time. The air is so little charged with vapour when the frost is intense, 
that the atmosphere appears of the deepest, most absolute black hue at night, 
whilst the stars shine with a degree of brightness that is not observable in more 
temperate climates... It is not extraordinary for the mercury. of the thermometer 
to fall five or six degrees of .Reaumur’s scale within an hour in Russia, when 
the atmosphere, after haying been clouded, is rendered clear by wind; \and this 
does not result from the wind itself being a. colder atmosphere, because the 
phenomenon mentioned. cecurs when. the wind comes from a, southern and. 
ac ually less cold region. On the other part, a north wind, when-the,weathe? 
is actually colder in that region, if it brieg clouds over a-certain more southern 
‘Tegion, will be accompanied by an equally considerable rising of the mercuryof, 
the thermometer; It appears that it is from those phenomena: that, ithe 
coldest period of the day is about the time of sun-rise ; this is generally. the case 
in Russia, where the nights are ordinarily without wind, anda breeze or, more: 
considerable, degree of wind occurs about this time, rendering the atmosphere: 
more. clear than it is ordinarily during a few hours previous to sun-rise. ‘In 
and, a precipitation, of mist or dew but rarely occurs when the sky ds: 
clouded, in the autumnal season; because there, with a clouded atmosphere, 
seas. Persons trayelling in)Russia, in, the night, may commonly observea mist 
or .dew. to,appear and disappear several times..in succession: in-a-nightits 
disappearance always following the: diffusion-of clouds inthe sky, and its re-ap- 
Begrapesve nang liam the aimesph ere, beeoming cleats di es iow se cid? willbe 
It does not appear probable that the elevation of temperature, ensuing from 
aclouded sky, above. deseribed,., proceeds—at, least -not jin any, considerable 
pepeesiiReniron the diffusion of heat, resulting from the:condensation of gasses 
in the atmosphere into aqueous particles; because it happens when the clouds 
9° 
M.M. New Serics—Vot. II. No. 9. 2R 
