2S6 Rev. J. Macgarvie's Thermometrical Observations at 



ing manner, and that, were a man to take only the means at 7 

 A. M., 1^ P. M., and 4 p. M. ; or ten in the morning and ten at 

 night, as others propose, he might obtain the extremes of the 

 range ; which might give him data for determining the tempera- 

 ture of the earth ; but they cannot be depended upon, when in- 

 tended to furnish correct notions respecting the temperature of 

 the atmosphere, and its variations. The thermometer employed 

 was the very delicate one made by Troughton, formerly in your 

 possession, on which, you are aware, all dependence can be 

 placed. 



Register of the Thermometer, at Pitt- Town, New South Wales, on 

 the hanks of the Hawheshury, on 5th January 1827, a fair ave- 

 rage midsummer day, with a strong cool breeze, blowing all day. 

 At mid-day, grass 88°. Sand 98°. Water 78°. Air 79^° to 



strong cool gusts of west wind, clear sun, hot. 

 Av^erage rise in the hour 2 degrees. 



Strong cool breeze increasing. 



Wind fallen, descent in 50 minutes |ths oi a degree, 

 rage rise in the hour a half degree. 



Ave- 



Average rise in half an hour 4 degrees. 



And a shade less, wind nearly ceased. At this rate, not to 



be depended on, only for a few minutes. 

 Breeze. 



Ditto fresher, and hot. 

 Average rise 3ith degrees in the hour. 



Sun overcast, breeze strong, descent 1 |th degrees. 



Breeze strong, sun bright. 



Ditto, do. descent 1 ^ degree per hour. 



Ditto, do. increasing. 



Ditto, do. overcast. 



Very strong, loud, shrill wind, descent 1 degree. 



Severe gust. 



Very violent gust, descent half a degree. 



Nearly calm. 



Still ditto. 



Cold breeze, descent fths of a degree. 



Sunset. 



Moon clear on thermometer. 



Thus throwing out the 84% at 1 o'clock, for which I will not 

 be answerable, the rise from 10 to 2 is equal to 5|°, while, to fall 

 the same quantity, it took six hours, making about 1 1° in the 

 one case, and 1° in the other, per hour. 



