A year's weathek. 403 



would do if born in spring. The effect of varying temperatures 

 on clusters of eggs of butterflies may produce two distinct forms, 

 one with the white wings blackened at the base, the other 

 blackened at the tips ; one of these is the type form, the other 

 a distinct variety. During the glacial period the short cold 

 summers allowed of only single-brooded butterflies, but the 

 increased heat and longer days have permitted in some cases 

 of another brood — and in other cases of two more broods — 

 arising from the same insects during the year, giving rise to the 

 dimorphic and trimorphic insects of the biologist. 



Weather for November, 1792,— one hundred years ago: — 

 3rd, primroses in bloom. 12th, flocks of fieldfares pasturing on 

 the land; late crops of barley housed to-day. 15th, a violent 

 storm of wind and hail. 16th, Seagulls in abundance inland. 

 This month was gloomy ; colds under the fashionable term of 

 influenza have prevailed very generally both the last and present 

 month. Fall of rain, 1-20 inches. 



A hundred years ago November was even drier than our 

 somewhat dry November this year. 



December 22nd, 1892. 



DECEMBER. 



The rain fell on 19 days, reaching a total of 2-52 inches, 

 the driest December since 1885, when the fall of rain was 2*17 

 inches. Our avei'age rain in the last month of the year is 4*65 

 inches, so that we were more than two inches below our average, 

 which is a mean of over 40 December rainfalls. Taking the 

 same month during this long period, the wettest December was 

 in 1876 with 10*59 inches, and the driest one in 1873 with 1*23 

 inches of rain. 



The month was cold. Just after Christmas we had intensely 

 severe weather, hoar frosts came day after day and the 

 thermometers sank very low before them. Taking outside 

 temperatures from the 26th to the 30th, we registered 18, 11, 

 13, 23, and 28 degi-ees respectively; the registration of 11 

 degrees on the 27th, marked the coldest night of the year, with 

 21 degrees of frost; the second coldest was the next night with 



