42 



RESULT OF METEOROLOGICAL OBSERVATIONS 



Frost. 



Frost is recorded in every month of the warmer half of the year, and quite fre- 

 quently in the first half of June. In 1848 there were four mornings of frost 

 between June 1 and 13; in 1843, June 2, ice formed one-eighth of an inch thick; 

 frost occurred June 22 and 23, in 1846; July 1, 1835; August 1 and 2, 1842; 

 August 23, 1835; August 25, 1832, August 29, 1859. 



State of the Weather. 



The number of fair and of cloudy days in each month were published by Dr. 

 Hildreth, in Silliman's Journal, for a number of years ; to these were added the fair 

 days recorded by Mr. Wood, making in all, between 1818 and 1859, 37 results for 

 each month, excepting April, May, and December, for which the number of years 

 is but 36. 



Table XII. — Average number oe Fair Days in each | 



Month 



DURING THE PERIOD 1818 TO 1859. 1 



January- 



. 13.8 



July .... 21.9 



February . 



. 13.9 



August . . . 21.7 



March 



. 1«.7 



September . . . 20.3 



April . 



. 17.7 



October . . .18.9 



May . 



. 19.4 



November . . . 14.5 



Juue . 



. 20.3 



December . . . 12.7 



The numbers show a regular progression during the year. In December the 

 number of fair days is least; they increase each month and reach their maximum 

 in July, after which month they again gradually diminish. 



The greatest number of fair days recorded in any one month is 30 (in July and 

 August), and the least number, 3 (in November); the average aggregate number 

 of fair days in any one year is 21 If (and of cloudy days consequently 153|), vary- 

 ing between 170 (in 1858), and 262 (in 1830). It is, therefore, comparatively sel- 

 dom that in any year the number of fair and of cloudy days are equal. 



Summing up the number of fair days in each year, we have the following results: — 



Table XIII. 





0. 



1. 1 2. 



3. 



4. 



5. 



6. 



7. 



8. 



9. 



1810 



. - . 



. - . 











... 



















193 



1820 



181 



174 



180 



... 



... 







... 



... 



242 



208 



1830 



262 



205 



216 



222 



255 



221 



219 



224 



248 



228 



1840 



204 



205 



215 



193 



209 



236 



201 



198 



211 



226 



1850 



233 



229 



203 



221 



231 







228 



200 



170 



190 



Atmospheric Pressure. 



The barometer was not exposed to the natural temperature of the air, but was 

 suspended in a room heated during the winter. Between 1829 and 1832, Novem- 

 ber, an ordinary instrument was used ; from the first of November, 1832, however, 

 a more reliable instrument was substituted ; it was made by Dr. Peters, of Pitts- 



