400 ANNUAL OF SCIENTIFIC DISCOVERY. 



ter during that time being also 30.55, or also fully half an inch above the average. The 

 altitude of 30.90, which continued without change for 12 hours, from the 27th at 9 P. M. 

 to the 23th at 9 A. M., was the highest observed here for five years, or since that of April 

 2, 1844, viz. 30.92. 



Temperature of each Month during the last Nine Years at Boston, 



Cambridge, and Greenwich. 



Jan. Feb. JVlar. Apr. May. June. 



Boston, . 



Cambridge. 



Greenwich, 



Boston, . 



Cambridge, 



Greenwich, 



The average quantity of rain in each month, at Cambridge, during the last six years, 

 and at Greenwich during the last nine, was as follows, in inches: 



Cambridge, . 

 Greenwich, 



Cambridge, 

 Greenwich, 



At Cambridge, the greatest quantity falls in December, the least in April. 



Greenwich, October, March. 



Greatest quantity in any month at Cambridge (in G years), Nov. 1846, 10.43 inches. 

 Least " " Jan. 1849, 0.72 



Greatest quantity in any month at Greenwich (in 9 years), Oct. 1841, 6.0 

 Least June,lS49, 0.2 



The mean temperature of each of the last nine years was as follows, viz. : 



1841. 1842. 1843. 1344. 1S45. 1846. 1847. 1848. 1849. Mean. 



(( 

 It 



In the course of the nine years the thermometer was : 



Boston. Cambridge. Greenwich. 



Highest, . . June 30, 1341, B7 July 12, 1845, 100 July, 1846, 92* 



Lowest, . . al!' if if}!' 2* Jan> 5 > 1S41 > ~~ 15 Jan ' 1S41 > 4 



Eange, . . 9S$ 115 88* 



This temperature of 97 on June 30th, 1841 , was of very short duration ; and within two 

 hours, or at 5 P. M., was followed by a shower of destructive hail of the size of nutmegs; 

 the largest hail, here, of which we have an account. The next greatest altitude in Boston 

 in the nine years was 96J, on July 13th last. 



Boston. Cambridge. Greenwich. 



The warmest month was, July, 1842, 74 17 July, 1847, 73.03 j Jjjjv \f, ? 65 40 

 The coldest Jan. 1844, 20.00 Jan. 1844, 15.3 Feb.', 1845^ 32.7 



Difference, . 54.17 57.7 32.7 



Greatest difference between any two consecutive months, at Boston, 18.16, between 

 November and December, 1S45 ; at Cambridge, 18. 7, between the same ; and at Green- 

 wich, 13.l, between November and December, 1846. 



At Greenwich, the colde.st month averaged two thirds of a deeree abore the freezing- 

 point; at Boston, 12, and at Cambridge, nearly 17 below the same point. The greatest 

 sudden chansre (rise) in the thermometer in the nine years took place in 54 hours, Jan. 

 5-7, 1841, viz. at Boston, 56 ; Cambridge, 71 ; and at Northampton, near Amheist, 83. 



