1819.] Dr. Burney’s Meteorological Observations. 455 
the Annals, it will not now be necessary to enter on any expla- 
nation of them. 
Evaporation. 
The quantity that has evaporated here this year is beyond all 
former observations ; indeed, itis 15} inches more than m 1817, 
and double that of 1816. In June last it amounted to 9.!;th 
inches ; and from the 3d to the 9th of that month, the lead 
evaporator, six inches square, exposed to the weather, actually 
Jost half an inch regularly every 24 hours, with easterly and 
north-easterly winds, and with a mean temperature of 64°7°. 
Under all the circumstances that attended this evaporation, a 
pond of water 15 inches deep and of any square area, would, in 
30 days (taking day and night together), be entirely dried up. 
Hence when we see or hear of springs being partly dried up m 
summer, after a long drought, accompanied by a high tempera- 
ture, our astonishment ceases. In April, May, June, July, 
August, and September, the quantity that evaporated was 413. 
inches. In October, November, December, January, February, 
and March, it amounted only to eight inches ; so that the evapo- 
ration in the spring and summer months was five times more 
than in the months of autumn and winter. In the spring and 
summer of 1817, it was four times as much as in autumn and 
winter of that year. 
Rain, &c. 
The quantity of rain, as might have been expected from so 
dry a summer, is 2°63 inches less than in the preceding year. 
The mean of the last three years’ rain here is 30°35 inches; and 
the mean of the last two years’ rain at Tottenham is 25°39 inches ; 
the mean difference for several years is about four inches a year 
more at Gosport than at Tottenham and its neighbourhood. But 
Tottenham has less attractions of the lower strata of clouds, in 
regard to sea, hills, &c. than Gosport, which may account for the 
difference in the average quantity of rain. 
Comparison of the Evaporation, and the Quantity of Rain at 
Gosport, Bushey Heath, near Stanmore, and Tottenham, in 
the Year 1818, viz. 
Evaporation. Rain. 
At Gosport. ....++.06+ 49°800 in, 6... seer eee 27-940 in. 
At Bushey Heath...... AQORB! Cada ae Fees Sees 21°405 
At Tottenham ........ BAO!) MRS Se. bs . 25°950 
We know not how to account for the comparative difference 
that appears in the evaporation at the latter place, unless the 
evaporator there is partly sheltered from the free and combined 
action of the sunshine and winds. ; 
Variation of the Magnetic Needle. 
From about 100 recent morning and noon observations, with 
