You may then observe the Surface of the Water next the Light, refract the Sun’s Rays, and produce the primary Colours, particularly the +red+ and +green+: which tho’ _transient_, _continue_ to be _seen_ in Succession; as Vapours rise above the Surface of the Water. Their _first_ Ascent is plainly discoverable: remaining above its Surface, in the Form of _small Dust_, gently agitated, not _separately_ but as a _whole_. Nor do they seem to rise into Steam, till assisted by the Action, and Contact of _dry Air_, which like _dry_ Spunges, _licks off_ and absorbs the small Dust already accumulated by the Force of the Heat from below, and then becomes visible under the Appearance of Steam, flying off in distinct hollow Vesicles. The more _still_ the Air of the Room, the more slowly will the Spunges of Air come in Contact with the Body of small Dust.—Besides the small Dust already mentioned; the Heat will detach solid Globules of Water; which will remain floating on the Surface of the Body of Water: till the dry Air descends and transports them with it; the Air at the same Instant dissolving the solid Globules into hollow Vesicles. But the most extraordinary Phenomenon, and which cannot be mistaken, is, that as soon as a Spunge of Air has dipped into the Surface of Water, and received its Lading; the Vesicles continue to accumulate, till another fresh Spunge descends in a similar Form, which may be traced upon the Surface of the Water, and seen in its Shadow, or rather in Beams of Light at the Bottom of the Bason, at the Instant it has flown off with its Burden: for that Part of the Surface of the Water transmits new Rays of Light, on Removal of the Vapour carried away by the Dip and Play of Air. 248. The Removal of the Vapour, likewise exhibits a curious Appearance on the Surface of the Water: which seems as if divided into irregular Parcels detached from each other; like the reticular Daplings visible on the under Side of Clouds elevated to the highest Stratum of the Atmosphere, and there evaporating or dissolving. 249. So powerful is the Attraction between Air and Water; that, while the Steam is rising above and round the Sides of the Bason; _Waves of fresh Air_, by Intervals, press the exterior Parts of the Steam _inwards_, in order to get at the Surface by descending into the Bason.