(And Iron rusts least in rainy Weather: [the Air being then driest,] descending from the upper Regions. Abr. Ph. Tr. V. 3, P. 546.)”
It is said also that “in Jamaica the Clouds gather, and shape according to the Mountains: so that old Seamen will tell you each Island towards Evening, by the Shape of the Cloud over it.”
The Sea-Breeze, being counterpoised by Descent of the etherial Air, produces a calm.
The same Author likewise says, that “the Clouds begin to gather about 2 or 3 o’Clock in the Afternoon at the Mountains, and do not embody first in the Air, and after settle there, but settle first and embody there: the rest of the Sky being clear till Sun-set. So that they do not pass near the Earth in a Body, and only stop where they meet with Parts of the Earth elevated above the rest; but precipitate from a very great Height, and in Particles of an exceeding rarified Nature; so as not to obscure the Air or Sky at all: that great Variety of beautiful Colours in the Canopy of Heaven being raised to a much greater Distance [he means Height] in Jamaica than it is here.” Abr. Ph. Tr. V. 3, P. 557.
(Prognostics of Weather, at certain Periods of the Moon, are mentioned by Captain Langford. Lowthorp’s Abr. Phil. Trans. Vol. 2, Page 105.)
[68]The Depression of a Torrent of Air in the Form of an hyperbolic Solid, contracting as it descends to the Earth, in Proportion as its Density encreases; may furnish a Hint towards the Solution of a Difficulty how to account for the Augmentation of vesiculous Vapours into large solid Drops, frequent during Summer-Showers.
[69]Mons. Saussure’s valuable “Essais sur L’Hygrometrie,” throw new Light on the Doctrine of Rarefaction and Condensation not unfavourable to the Hypothesis here advanced. Page 260.
[70]Ice, when exposed to marine acid Air, is dissolved by it, as fast as if it touched a red hot Iron. See Cavallo’s Treatise on Air, Page 727. Also Priestley’s Experiments and Observations, Vol. 1, Page 148.
[71]“The water remains transparent or colourless, tho’ saturated with marine acid Air, and by a very gentle Degree of Heat, the Gass may be again expelled from it, as it is expelled from Spirit of Salt.”
This Observation is applicable to the Transparency of Vapours, in the Air, tho’ mixed with the marine Acid exhaled from the Sea: for when the acid or Sea Air is mixed with Alkaline or Land Air, they instantly combine; lose their Elasticity, and form a white visible Substance or Cloud. Cavallo, Page 728. Priestley’s Exp. and Obs. Vol. 2, Page 293.