HISTORY OF VEHMONT. 7S 



horses and sleighs passed over the ice, for five 

 or six davs. This was the be&'inninar of such 

 im effect, as that which is mentioned in the an- 

 cient account. The ice became fixed and per- 

 manent on February second ; and continued in 

 this state until February 10th. During that time 

 I found the lowest degree of Farenheit's ther- 

 mometer to be— 9 degrees ; the greatest degree 

 was 28 degrees : and the mean heat was 13 de- 

 grees. It may be presumed therefore, that the 

 freezing of the bays of which Wood speaks, 

 could not have taken place, or continued, in a 

 less degree of cold than this. This will give 

 us 13 degrees of Farenheit's thermometer, as 

 the mean heat which took place during eight or 

 ten weeks of the winter, so far back as the year 

 1630. By the meteorological observations 

 which I made in the UniA^ersity at Cambridge 

 for seven years, from 1780 to 1788, I found the 

 mean heat in the month of December was 29 

 degrees 4 tenths ; in January it was 22 de- 

 grees 5 tenths ; and in February it was 23 

 degrees 9 tenths. These numbers express 

 the present temperature of the winter at Boston. 

 If this computation be admitted, the change of 

 temperature in the winter, at Boston, from the 

 year 1630 to the year 1788, must have been 

 from ten to twelve degrees. 



A permanent alteration in the temperature of 

 tlie climate or atmosphere, supposes an alteration 

 e(^ally great and jx^rmanent, in the heat of the 

 earth. Whether the heat of the earth is thus 

 affected by cultivation, and what will be its ef- 

 fects, I endeavoured to ascertain in the follow^ 

 ing manner. On the 2Sd of May, 1789, I bunk 



