v BELIEF AND EVIDENCE 95 



depict Christmas scenes. Snow is apparently as essential 

 a part of every Christmas story or picture as the ghost 

 or the haunted chamber, yet our own experience tells 

 us that one is almost as rare as the other, and that the 

 association of snow with that day is more a matter of 

 imagination than of fact. If, however, we look further 

 back, a reason may be found for colder weather at 

 Christmas than that now usually experienced. On 

 account of the change from the Julian to the Gregorian 

 Calendar in 1752, Christmas now occurs thirteen days 

 earlier than it did. Old Christmas Day, Jan. 7, 

 marks the date upon which the festival was formerly 

 celebrated ; and there have been considerable falls of 

 snow after Christmas which would have occurred at 

 Christmas or before if the Julian Calendar had been 

 still in use. 



Tradition, and general impressions of elderly people, 

 are, indeed, of little value in deciding whether any 

 permanent change of climate has taken place. The 

 only trustworthy test is provided by records of rain- 

 fall, temperature or other meteorological observations 

 made systematically with suitable instruments. Such 

 records go back for 150 years or so, and when they are 

 examined critically they are found to give no decided 

 indication of any progressive change, either for the 

 better or worse. From an examination of old records, 

 and of the long series of observations made at Green- 

 wich, Sir John Moore was able to show to the British 

 Association in 1908 that no appreciable change has 

 taken place in the climate of the British Isles during 

 the past six centuries. It is of no use to place a 

 popular belief in such a change by the side of such 

 a conclusion arrived at as the result of open-minded 

 and careful inquiry. The responsibility of proving 



