DISTRIBUTION OF TEMPERATURE ON THE EARTH. 233 
order of the intensity of the cold. This cold was very evident 
in northern Germany, but vanished at the Alps; indeed in Italy 
there was a mild temperature increasing southwards. In Fe- 
bruary the cold had decreased at the above-named places; but 
was intense from Dantzic to Milan, and was inconsiderable even 
in Palermo; the maximum fell on Berlin. In March the maxi- 
mum was in southern Germany and northern Italy, and in April 
this cold was replaced by a generally-distributed warmth. 
The propagation of an unusual warmth in winter is generally 
attended by stormy south winds, and is therefore too rapid to 
be very distinctly shown in the monthly means. Frequently a 
very warm south-west wind meets a very cold north-east one ; 
in the localities situated to the south there is at such times an 
exceedingly mild temperature, and in the northern parts an in- 
tense cold, and on the borders we find very variable weather. 
As recent examples, we may mention December 1839, when 
Berlin was several times included in the cold stream, in southern 
Germany it was very warm, and in Petersburg on the contrary, 
intensely cold. But even in the monthly means the same phe- 
nomena are evidently visible. In December 1838 the cold which 
prevailed in Europe extended from Torneo to Palermo, decrea- 
sing towards the west and not sensible in America. In January 
1809 the whole of southern Europe enjoyed very mild weather, 
while the cold, which was probably prevented from extending 
southward by south winds, was concentrated in northern Eu- 
rope, and increased from Berlin to Dantzic, Stockholm and Tor- 
neo; it then passed off westward, for it increased considerably 
in Scotland, and was felt in America. In February the warmth 
extended up to Dantzic, the cold remained only in Stockholm 
and Torneo, but was considerable in America. In March it 
forced its way again southwards, for it again appeared in Dantzic 
and Berlin. In April it spread over all Europe, but had left 
America. 
A diminution of temperature in winter is principally caused 
by north winds; but in spring it is often a secondary phenome- 
non. ‘The dispersion of a south by a north wind is in general 
accompanied by a fall of snow, which on lofty mountains takes 
place at a great height even during the continuance of the south 
stream. ‘The masses of snow which are thus collected during 
the winter exert their refrigerating influence on the spring 
warmth which appears on the plain. Perhaps from this reason 
VOL. IIL, PART x. R 
