As hail is only produced in summer, and is always attended with storms, some philosophers have believed that the sudden departure of electricity from a cloud may effect something yet unknown in this phenomenon; but it may happen in summer independent of electricity, because the aqueous vapour is then raised higher in the atmosphere, whence it has further to fall, and there is warmer air below for it to fall through.]
[Or sink in silver dews. l. 18. During the coldness of the night the moisture before dissolved in the air is gradually precipitated, and as it subsides adheres to the bodies it falls upon. Where the attraction of the body to the particles of water is greater than the attractions of those particles to each other, it becomes spread upon their surface, or slides down them in actual contact; as on the broad parts of the blades of moist grass: where the attraction of the surface to the water is less than the attraction of the particles of water to each other, the dew stands in drops; as on the points and edges of grass or gorse, where the surface presented to the drop being small it attracts it so little as but just to support it without much changing its globular form: where there is no attraction between the vegetable surface and the dew drops, as on cabbage leaves, the drop does not come into contact with the leaf, but hangs over it repelled, and retains it natural form, composed of the attraction and pressure of its own parts, and thence looks like quicksilver, reflecting light from both its surfaces. Nor is this owing to any oiliness of the leaf, but simply to the polish of its surface, as a light needle may be laid on water in the same manner without touching it; for as the attractive powers of polished surfaces are greater when in actual contact, so the repulsive power is greater before contact.]
[The blue mist. l. 20. Mists are clouds resting on the ground, they generally come on at the beginning of night, and either fill the moist vallies, or hang on the summits of hills, according to the degree of moisture previously dissolved, and the eduction of heat from them. The air over rivers during the warmth of the day suspends much moisture, and as the changeful surface of rivers occasions them to cool sooner than the land at the approach of evening, mists are most frequently seen to begin over rivers, and to spread themselves over moist grounds, and fill the vallies, while the mists on the tops of mountains are more properly clouds, condensed by the coldness of their situation.
On ascending up the side of a hill from a misty valley, I have observed a beautiful coloured halo round the moon when a certain thickness of mist was over me, which ceased to be visible as soon as I emerged out of it; and well remember admiring with other spectators the shadow of the three spires of the cathedral church at Lichfield, the moon rising behind it, apparently broken off, and lying distinctly over our heads as if horizontally on the surface of the mist, which arose about as high as the roof of the church. There are some curious remarks on shadows or reflexions seen on the surface of mists from high mountains in Ulloa's Voyages. The dry mist of summer 1783, was probably occasioned by volcanic eruption, as mentioned in note on Chunda, Vol. II. and therefore more like the atmosphere of smoke which hangs on still days over great cities.
There is a dry mist, or rather a diminished transparence of the air, which according to Mr. Saussure accompanies fair weather, while great transparence of air indicates rain. Thus when large rivers two miles broad, such as at Liverpool, appear narrow, it is said to prognosticate rain; and when wide, fair weather. This want of transparence of the air in dry weather, may be owing to new combinations or decompositions of the vapours dissolved in it, but wants further investigation. Essais sur L'Hygromet, p. 357.]
[Round the gelid hill. l. 20. See additional notes, No. XXVI. on the origin of springs.]
25 "NYMPHS! YOU then guide, attendant from their source,
The associate rills along their sinuous course;
Float in bright squadrons by the willowy brink,
Or circling slow in limpid eddies sink;
Call from her crystal cave the Naiad-Nymph,
30 Who hides her fine form in the passing lymph,
And, as below she braids her hyaline hair,
Eyes her soft smiles reflected in the air;
Or sport in groups with River-Boys, that lave
Their silken limbs amid the dashing wave;
35 Pluck the pale primrose bending from its edge,
Or tittering dance amid the whispering sedge.—
"Onward YOU pass, the pine-capt hills divide,
Or feed the golden harvests on their side;
The wide-ribb'd arch with hurrying torrents fill,
40 Shove the slow barge, or whirl the foaming mill.
OR lead with beckoning hand the sparkling train
Of refluent water to its parent main,
And pleased revisit in their sea-moss vales
Blue Nereid-forms array'd in shining scales,
45 Shapes, whose broad oar the torpid wave impels,
And Tritons bellowing through their twisted shells.
"So from the heart the sanguine stream distils,
O'er Beauty's radiant shrine in vermil rills,
Feeds each fine nerve, each slender hair pervades,
50 The skins bright snow with living purple shades,
Each dimpling cheek with warmer blushes dyes,
Laughs on the lips, and lightens in the eyes.
—Erewhile absorb'd, the vagrant globules swim
From each fair feature, and proportion'd limb,
55 Join'd in one trunk with deeper tint return
To the warm concave of the vital urn.
II. 1."AQUATIC MAIDS! YOU sway the mighty realms
Of scale and shell, which Ocean overwhelms;
As Night's pale Queen her rising orb reveals,
60 And climbs the zenith with refulgent wheels,
Car'd on the foam your glimmering legion rides,
Your little tridents heave the dashing tides,
Urge on the sounding shores their crystal course,
Restrain their fury, or direct their force.