304 Notices Regarding the Climate in Russia. {Seer. 
HE 
and in summer colder, than the superambient atmosphere —the sener sian 
s, (which, 
about Moscow than in Ireland. re 
“Phe communication of heat from the earth to the atmosphere, when the 
temperature of the former is higher than that of the latter, does not take 
place ‘to any considerable extent in plain countries devoid of forests—or, to 
speak with more precision, it takes place to but a small extent in comparison 
with what occurs in respect’ to the sea. Ina country ¢overed with forests of 
old trees, whose’ roots petietrate deep into the earth, it ‘is mach more re- 
markable. ‘The atmosphere, when it is perfectly calm, has been observed two or 
three‘degrees warmer in the centre of a large forest than inthe’ plain, surround- 
ing it." Reflection of the heat radiated from the eatth’ by the branches of the’ 
trees may perhaps contribute somewhat to this effect, but it is not’ the sole 
cause of it, and it is not’ probable that it can contribute much to it ‘in winter, 
when’ the trees are without’ leaves, A thermometer placed’ in the centre of 
a'hollow tree in winter, ‘always’ indicates a higher temperature than in the 
open’ atmosphere: and this does not arise from the vitality of the tree develop- 
ing heat ; the same result may be observed in a perfectly dead tree as in a 
living one’; and it oceurs even in a post of wood, or a wall, and’ that to a’ 
greaterextent’as they penetrate deeper into the earth, and as their dimensions 
are’ more! considerable. © When the temperature of the atmosphere is but 
little above'the freezing point, snow about the basis of posts, columns of 
stone, ‘or walls, ‘is observed to become thawed, as well as- that around the 
trunks|of trees. This result takes place to an extent in respect to trees of differ- 
ent species, inproportion to the extent of their roots, and the depth they pene- 
trate into ‘the earth ; and it is more Considerable in respect to a large tree than 
toa smaller’one of the same species. In the’ case of mist freezing on the trees, 
in’Russia, covering their branches? with a layer of ‘ice, it is always remarkable 
that this takes place more extensively on small and young than in larger and 
older trees of the same species; when, ‘on the former, ‘this coating of ice covers 
not only all the small branches, but the trunk of the tree, even to @ small dis- 
tance fromiits root, it occupies on the latter only the branches, and bgt id 
more or less of the superior part ofthe trunk: ‘On trees of’ the same species, 
planted at the same time, of equal growth, the coating of ice may be observed ' 
to terminate almost ‘precisely at' the same distan¢e fromthe earth.’ “When the 
cold is greater, all the trees become thus ’cased in ice ; but it is the largest and 
oldest trees, whose roots penetrate deepest into the earth, that are the last to 
suffer this, as well as the first from which it ‘disappears; ‘when’ the’ frost’ be- 
comes less severe. Nt DOGS ae 2 
» The abstraction of heat from the atmosphere by the’ earth,’ when the latter” 
is colder than ‘the former, is too evident ‘to require any illustration, as it is 
o r 
