288 ' Meteorological Register. 



is enclosed in a box, and suspends a weight upon a small cylinder, 

 which, of course, increases in diameter at every degree marked upon 

 the dial, which is upon the outer surface, the whole adjusting itself 

 to the wind by a tail or rudder. The days marked fair agree almost 

 exactly with those of 1834, '3, being for the first of those years 

 two hundred and thirty one, and the second two hundred and thirty 

 two. The quantity of rain has been a fair average ; the heaviest 

 being the 10th of October, 3.63. The greatest change I have no- 

 ticed has been in the number of days marked "south winds" — of 

 those sultry winds, we had in 1833 sixty five days, and in '34 forty 

 days, and the corresponding years thirty and thirty four north wind 

 days against fifty of this year. To this we must mainly attribute the 

 low range of the thermometer for the latter. The variable winds 

 too have prevailed to a greater extent than usual. 



My other occupations have prevented my making any consecutive 

 observations upon the electrical state of the atmosphere ; perhaps 

 those days marked " thunder" may give you some idea upon that 

 subject. The land breeze, which generally springs up between eight 

 and twelve o'clock at night, has prevailed to about the same extent 

 as usual. You will observe that the mean of three daily observa- 

 tions gives the same result within a fraction, as the mean of two ex- 

 tremes per register thermometer. I would therefore recommend 

 the use of the latter in a climate like this, as being attended with far 

 less trouble ; the only objection is that the quicksilver in the mercu- 

 rial tube, is apt to become deranged when the instrument has been 

 long used. ~ 



At the time of the remarkable meteoric display in November, 

 1833, I did myself the honor of making to you some observations 

 upon the subject. I have not yet learned whether they reached 

 you.* I remain, sir, with high respect, 



Your very obd'nt serv't, A. Mallory. 



* They were received, and are cited in Vol. XXV. p. 401. — Ed. 



