156 BOARD OF AGRICULTURE. 



cisely at the point where they left it in the other. So thor- 

 oughly, as already stated, is the ground cooled by our severe 

 frosts, that it requires the action of the sun for several weeks 

 after the equinox, to call our trees into full life. But such is 

 the heat of our May and June, that vegetation, when once fairly 

 started, advances with rapid strides, and by the middle of June, 

 our growing season is probably on a level with that of the 

 south of England. We find that many of our fruit trees which 

 blossom, generally speaking, two or three weeks later than 

 those of the same description near London or Paris, ripen their 

 fruit at about the same time. Thus, from observations made 

 for several years near Cambridge, in England, it appears that 

 cherry trees which flowered, on an average, April 14th, ripened 

 their fruit June 27th — by no means an early period with us. 

 All seasons, early and late, says the late Mr. Lowell, are nearly 

 on a level, on the 10th of June. " It is familiar to every one, 

 that in Russia and Canada, the seasons are as forward as ours, 

 by the beginning of July." Midsummer probably occurs at 

 precisely the same time throughout the whole of the northern 

 temperate zone. 



3. The most striking circumstances, however, which dis- 

 tinguish the climate of every part of our country from that of 

 Great Britain, are our fierce extremes and the sudden and 

 extensive changes of our temperature. The zero of Fahren- 

 heit has been stated as the minimum of the thermometer at and 

 near London. Putting out of the question, however, extraordi- 

 nary seasons, this minimum may be fairly placed ten degrees 

 higher. With the same qualification, the greatest degree of cold 

 in the vicinity of Boston, may be fixed at about ten degrees 

 below zero ; being twenty degrees lower than the London min- 

 imum. This degree of cold is reached or approached in our 

 vicinity almost every year. 



We very rarely pass a winter which is not distinguished by 

 a few days of extreme cold, by which is meant, days on which 

 the mercury sinks below zero. The number of these days 

 varies, rarely exceeding five or six, and averaging three in a 

 season, and they often occur in immediate succession. Few as 

 they arc, they are amply sufficient to test the hardiness of our 

 trees and shrubs, for it is not likely that any plant that could 



