146 PHILOSOPHY OF STORMS. 



was north west on the 17th, nearly clear, some clouds in the 

 south. The barometer rose 33 one hundredths of an inch from 

 the 16th, and there was a little snow at two o'clock, P. M., of 

 the 18th, and the barometer did not fall much till the 19th. 



In a letter from the Hon. Henry Connor, of North Caro- 

 lina, in the southern part of the state, a little west of the 

 middle, he says "I was not at home when the storm took 

 place, but it was very severe, as much timber was blown 

 down : and the wind must have been from the south, as the 

 tops of the trees were all lying toward the north. 



Arrow No. 18| is added to the chart from Mr. Connor's 

 letter, and if the reader will add one for Professor Elder's 

 account, at Frederick, Md., the phenomenon of the inward 

 motion of the wind toward the centre of the storm becomes 

 very decided. 1 



Directions. By the Joint Committee. 



117. Thermometer. The thermometer should be placed 

 in a situation screened from the direct rays of the sun, and 

 also as free as possible from the contact, reflection and ra- 

 diation, of surrounding bodies. If a place free from radia- 

 tion cannot be procured, the effect of radiation may be ob- 

 viated by swinging the instrument briskly in the air, or fan- 

 ning it where it hangs. The self-registering thermometer 

 should be placed in a horizontal position out of doors, and 

 screened from the open sky; the lowest temperature to 

 which it sinks in the twenty-four hours should be noted. 

 From this temperature, and the two o'clock observation, 

 the mean is obtained. 



Some time, during the warmest part of the day, the instru- 

 ment should be held with the bulb uppermost, until the en- 

 amel index descends to the extremity of the liquid in the tube. 



1 The above condensed Statement of the Facts, and Rationale, were written 

 by the author in his individual capacity, and had not the sanction of the Com- 

 mittee. 



