METEOROLOGY. 35 
four in November, aggregate 6:7 deg.; and thirteen in December, 
ageregate 42-9 dee. This makes the total number of days in 
which the protected thermometer fell below the freezing point 100 
and the aggregate degrees of frost 640, which is considerably in 
excess of any previous record during the period of observation at 
this station. In connection with the intense and protracted frost 
of the first two months of the year, it may be asked if any expla- 
nation can be given tending to account for it. I have no doubt 
that the proximate cause was the distribution of pressure during 
the period while it lasted. When we look into the details we find 
that the prevailing winds were almost constantly from the north 
and east. In ordinary winters the greatest pressure is commonly 
over Spain and the adjacent parts of the Mediterranean and 
Atlantic, and decreases towards Iceland and the north of Europe. 
Hence the prevailing winds are largely from the south-west and 
bring mild and moist weather. But last year this state of things 
was reversed. The greatest pressure was over the Arctic regions, 
and over Scandinavia and West Russia, giving rise to northerly 
and easterly winds, and making us participants in no small degree 
of the Arctic severity of the climate from which they came. This 
is an explanation so far, but we cannot carry it any further back, 
or tell why there should have been a different distribution of 
pressure last winter from what is most common, although doubt- 
less it had its causes. Perhaps the extremely sudden change of 
temperature which took place in the b2ginning of October should 
not be passed over without remark. The mean temperature of 
the last week of September was 64°8 deg., which is higher than 
that of any other week in the year by more than 2 deg. The 
mean temperature of the first week of October was 46-9 deg., 
shewing a fall of almost 18 deg. ina single week. But if we 
compare with the last week of September the last week of 
October, say from the 24th to the 30th, we find the mean of the 
latter period to have been only 35:8 deg., so that in four weeks 
the mean temperature had fallen to the extent of 29 deg. ; that is 
. to say, from the warmest summer temperature to the average of 
the coldest period of winter. 
RAINFALL.—The total amount of rain or snow that fell during 
the year was 35°03 in., and the number of days on which it fell was 
193 (rain 179, snow 14); but on 27 of these the fall did not exceed 
-one-hundredth of an inch. The heaviest fall in 24 hours was on 
