Miscellanies. 209 
waters on the earth; while rivers and lakes are heated, mainly, by con- 
duction. That salt water is warmed more quickly than fresh, is shown 
by the pyrometer. In two experiments the index moved over 2600 
divisions of the scale in ten minutes, when the trough was filled with 
fresh water ; and in a little over five minutes when salt water was used. 
In thirteen minutes the index reached 3600, where fresh water boiled ; 
but the index passed to 4000 with salt water, in eight minutes, where it 
boiled. This agrees with the relative expansibility of salt water and 
pure; the latter being enlarged a tenth less than the former, when heat- 
ed from 32° to 212° F. The rate of cooling is also different. Boiling 
fresh water was left to cool, and subsided to 132° in ten minutes, while 
salt water subsided only to 140°. The waters of the ocean, then, ake 
heat more rapidly, and retain it longer than fresh-water lakes, which, 
when large, remain cold even in midsummer. The heat from the bot- 
tom, the shores, and the air, does not raise the temperature of Lakes 
Superior and Michigan much above that of iced water in the hot 
season. But for the presence of some such substance in the waters of 
the ocean, they would never be warmed. The substance to be employed 
for this purpose, must be freely soluble in water and have strong attrac- 
tion for heat. The sulphate of soda, for example, would have fur- 
nished these qualities, but would not have afforded a supply for man, 
almost as needful as water itself, the salt for common use, which is 
obtained in such immense quantities by solar evaporation. 
It may be said that both water and salt, are remarkably transcalent ; 
but it does not appear that substances which suffer the solar beam to 
pass with the greatest facility, will permit it to penetrate, to indefinite 
depths. It is not probable that the calorific portion of the sun’s light, 
affects the ocean much below the surface. 
_ This consideration may be of some avail to explain the currents of 
the ocean, which are caused, in a great measure, by the difference of 
Specific gravity of the waters, and the motion thus given to them by 
the diurnal revolution of the globe. The heavier particles incline to 
the equator, and the lighter to the poles. 
The color of sea water is, doubtless, affected by the sun’s light, at least 
in some measure, acting on the substances which it contains. 
4. Kenawha Gas—communicated by Mr. Tauns A. Lewis, of Ke- 
nawha C, H.. > Va being an extract, dged , from the Charles- 
ton Rarciions, 
The existence of large quantities of gas at various points, through- 
out the whole extent of the salt region on the Kenawha river, was 
known to the first white men that explored this beautiful valley, It ap- 
peared escaping through apertures in low ronan and springs of water. 
Vol. xix, No. 1.—April—June, 1845. 
