METEOROLO(iY. 35 



four' in Noveuaber, aggregate 6-7 deg.; and thirteen in December, 

 aggregate 42-9 deg. 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 Avas 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 Avhy 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 bsginning 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. in a 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 



