112 Dr. Holmes? meteorological observations. 
Dr. Chalmers, who in 1766 published an account of the weather 
and diseases of South Carolina, says, that in the remarkably hot sum- 
mer of 1752 he exposed a thermometer, at the distance of five feet from 
the ground, to the rays of the sun; andi in 15 minutes the mercury 
rose to the utmost height of the instrument, which was graduated to 
120 degrees only, and would have burst the vessel, had he not with. 
drawn it. From experiments, which he made afterward, he judged 
that the mercury would have risen 20 degrees higher. 
‘The mean diurnal heat of the different seasons, Hewatt observes, 
has been, upon the most careful observation, fixed at 64° in the spring, 
79° in'summer, 72° in autumn, and 52° in winter; and the mean noc-. 
turnal heat in those seasons, at 56° in spring, 75° in summer, 68° m 
autumn, and 46° in winter. gpecouling to this estimate, the medium 
heat of Charleston is 64°, that i is, 2° less than Mr. Matlack estimates 
the medium heat of Savannah. This difference of temperature might — 
be expected from the difference of latitude of the two places, and the 
proximity of Charleston to the sea. 
The quantity of rain, which fell in Charleston, 5 Se Carolina, in seven 
ayt 
successive years, according to governor on. 
Years inches Years inches Years inches 
1795 71°8 1798 45°2 1800 51°6 
1796 58*1 1799 75° 1801 42°9 
1797 55 
Mean quantity of rain in Caen for ten years, viz. from 1750 to 
1786, inclusively, according to governor Drayton. 
Spring —_ 609 inches Winter 6°01 inches 
Summer 12°73 . 
Autumn 16-99 Year 42°03 
