“As the wind, or great body of air, tends more from the opposite quarter, the lines or spikes—all regular, hard, or crisp features—gradually diminish, till they vanish.
“Before, and in a continued southerly wind, the mixture sinks slowly downward in the vial, till it becomes shapeless, like melting white sugar.
“Before, or during the continuance of a northerly wind (polar current), the crystallizations are beautiful (if the mixture is correct, the glass a fixture, and duly placed); but the least motion of the liquid disturbs them.
“When the main currents meet, and turn toward the west, making easterly winds, stars are more or less numerous, and the liquid dull, or less clear. When, and while they combine by the west, making westerly winds, the liquid is clear, and the crystallization well-defined, without loose stars.
“While any hard or crisp features are visible below, above, or at the top of the liquid (where they form for polar winds), there is plus electricity in the air; a mixture of polar current co-existing in that locality with the opposite, or southerly.
“When nothing but soft, melting, sugary substance is seen, the atmospheric current (feeble or strong as it may be) is southerly with minus electricity, unmixed with, and uninfluenced by, the contrary wind.
“Repeated trials with a delicate galvanometer, applied to measure electric tension in the air, have proved these facts, which are now found useful for aiding, with the barometer and thermometer, in forecasting weather.
“Temperature affects the mixture much, but not solely; as many comparisons of winter with summer changes of temperature have fully proved.
“A confused appearance of the mixture, with flaky spots, or stars, in motion, and less clearness of the liquid, indicates south-easterly wind, probably strong to a gale.
“Clearness of the liquid, with more or less perfect crystallizations, accompanies a combination, or a contest, of the main currents, by the west, and very remarkable these differences are,—the results of these air currents acting on each other from eastward, or from an entirely opposite direction, the west.