254 J. HOPKINSON METEOEOLOGICAL OBSEKVATIONS 



The mean thermometric dryness, also, was within half a degree in 

 the two years, and the total rainfall differed by less than one-tenth 

 of an inch. "While, however, 1878 commenced with warm and 

 ended with cold weather ; in 1880, on the contrary, January was an 

 exceptionally cold month, and December was exceptionally warm, 

 its mean temperature being higher than that of November ; and 

 although the total fall of rain in the two years may be said to have 

 been identical, in 1880 it was more xmevenly distributed, there 

 having been three months each with less than half an inch of rain 

 and averaging but 0-44in., while in 1878 there was no month with 

 less than an inch, and the three driest months averaged l'27in. 



Compared with 1879 the year 1880 was not nearly so universally 

 wet, gloomy, and cold ; the temperature indeed was considerably 

 higher, and although the mean amount of cloud recorded was but 

 slightly less than in 1879, the sky was much more frequently 

 perfectly free from cloud and less often completely overcast. 

 Although also the total rainfall in 1880 was not much less than 

 in 1879, the number of days on which rain fell was considerably 

 less. In each of these years the atmosphere was humid ; in each 

 also there was a marked preponderance of both north-easterly and 

 south-easterly winds. "While, however, in 1879 the mean pressure 

 of the atmosphere was about the average or rather below it ; in 

 1880, chiefly during the earlier months, it was very high, and this 

 perhaps may be considered the most exceptional feature in the year. 



In the winter of 1879-80 (December to Februaiy) the mean 

 pressure was unusually high, the mean temperature low, the 

 humidity great, and the rainfall below the average. In the 

 spring (March to May) the mean pressure was again high, the 

 mean temperature rather high, and the humidity and rainfall below 

 the average. In the summer (June to August) the mean pressure 

 and mean temperature were about the average or a little below 

 it, the humidity great (for the summer months), and the rain- 

 fall slightly above the average. In the autumn (September to 

 November) the mean pressure was about the average, the mean 

 temperature low, the humidity rather great, and the rainfall the 

 heaviest which is known to have been recorded at "Watford. 



In the following notes the general character of the weather in 

 each month, and its principal changes are briefly referred to. 



Jantjaet. — The coldest month in the year by nearly 10", and 

 with the least rainfall, either as rain or snow ; only once was 

 there rain without snow (0-02 in. on 7th). The first two days 

 were very warm (mean 50"- 1, max. 54''-3, min. 44''-9) ; the next 

 three colder (mean SS^-O, max. 47°-9, min. SP-S) ; then followed a 

 very cold period lasting to 29th, max. never reaching quite 39°, 

 and min. falling below 22° on eight days, and only once (6th) as 

 high as 32° ; the last two days were warmer (mean 34°- 6, max. 

 51°-6, min. 20°-l). Max. above 42° on 6 days, above 52° on 1 ; 

 min. below 32° on 26, below 22° on 8. and below 12° on 1. Pres- 

 sure, generally high, reached 30-694 ins. on 7th, and 30-677 ins. on 

 21st. Wind northerly to E. from 10th to 28th. 



