3. There are numerous perpendicular fissures in the rocks of Derbyshire, in which the ores of lead and copper are found, and which pass to unknown depths; and might thence afford a passage to steam from great subterraneous fires.
4. If these waters were heated by the decomposition of pyrites, there would be some chalybeate taste or sulphureous smell in them. See note in part 1. on the existence of central fires.]
Impetuous steams in spiral colums rise
Through rifted rocks, impatient for the skies;
Or o'er bright seas of bubbling lavas blow,
180 As heave and toss the billowy fires below;
Condensed on high, in wandering rills they glide
From Maffon's dome, and burst his sparry side;
Round his grey towers, and down his fringed walls,
From cliff to cliff, the liquid treasure falls;
185 In beds of stalactite, bright ores among,
O'er corals, shells, and crystals, winds along;
Crusts the green mosses, and the tangled wood,
And sparkling plunges to its parent flood.
—O'er the warm wave a smiling youth presides,
190 Attunes its murmurs, its meanders guides,
(The blooming FUCUS), in her sparry coves
To amorous Echo sings his secret loves,
Bathes his fair forehead in the misty stream,
And with sweet breath perfumes the rising steam.
195 —So, erst, an Angel o'er Bethesda's springs,
Each morn descending, shook his dewy wings;
And as his bright translucent form He laves,
Salubrious powers enrich the troubled waves.
[Fucus.l. 191. Clandestine marriage. A species of Fucus, or of Conserva, soon appears in all basons which contain water. Dr. Priestley found that great quantities of pure dephlogisticated air were given up in water at the points of this vegetable, particularly in the sunshine, and that hence it contributed to preserve the water in reservoirs from becoming putrid. The minute divisions of the leaves of subaquatic plants, as mentioned in the note on Trapa, and of the gills of fish, seem to serve another purpose besides that of increasing their surface, which has not, I believe, been attended to, and that is to facilitate the separation of the air, which is mechanically mixed or chemically dissolved in water by their points or edges; this appears on immersing a dry hairy leaf in water fresh from a pump; innumerable globules like quicksilver appear on almost every point; for the extremities of these points attract the particles of water less forcibly than those particles attract each other; hence the contained air, whose elasticity was but just balanced by the attractive power of the surrounding particles of water to each other, finds at the point of each fibre a place where the resistance to its expansion is less; and in consequence it there expands, and becomes a bubble of air. It is easy to foresee that the rays of the sunshine, by being refracted and in part relieved by the two surfaces of these minute air-bubbles, must impart to them much more heat than to the transparent water; and thus facilitate their ascent by further expanding them; that the points of vegetables attract the particles of water less than they attract each other, is seen by the spherical form of dew-drops on the points of grass. See note on Vegetable Respiration in Part I.]
Amphibious Nymph, from Nile's prolific bed
200 Emerging TRAPA lifts her pearly head;
Fair glows her virgin cheek and modest breast,
A panoply of scales deforms the rest;
[Trapa, l. 200. Four males, one female. The lower leaves of this plant grow under water, and are divided into minute capillary ramifications; while the upper leaves are broad and round, and have air-bladders in their footstalks to support them above the surface of the water. As the aerial leaves of vegetables do the office of lungs, by exposing a large surface of vessels with their contained fluids to the influence of the air; so these aquatic leaves answer a similar purpose like the gills of fish; and perhaps gain from water or give to it a similar material. As the material thus necessary to life seems to abound more in air than in water, the subaquatic leaves of this plant, and of sisymbrium, coenanthe, ranunculus aquatilis, water crowfoot, and some others, are cut into fine divisions to increase the surface; whilst those above water are undivided. So the plants on high mountains have their upper leaves more divided, as pimpinella, petroselinum, and others, because here the air is thinner, and thence a larger surface of contact is required. The stream of water also passes but once along the gills of fish, as it is sooner deprived of its virtue; whereas the air is both received and ejected by the action of the lungs of land-animals. The whale seems to be an exception to the above, as he receives water and spouts it out again from an organ, which I suppose to be a respiratory one. As spring-water is nearly of the same degree of heat in all climates, the aquatic plants, which grow in rills or fountains, are found equally in the torrid, temperate, and frigid zones, as water-cress, water-parsnip, ranunculus, and many others.
In warmer climates the watery grounds are usefully cultivated, as with rice; and the roots of some aquatic plants are said to have supplied food, as the ancient Lotus in Egypt, which some have supposed to be the Nymphæa.—In Siberia the roots of the Butemus, or flowering rush, are eaten, which is well worth further enquiry, as they grow spontaneously in our ditches and rivers, which at present produce no esculent vegetables; and might thence become an article of useful cultivation. Herodotus affirms, that the Egyptian Lotus grows in the Nile, and resembles a Lily. That the natives dry it in the sun, and take the pulp out of it, which grows like the head of a poppy, and bake it for bread. Enterpe. Many grit-stones and coals, which I have seen, seem to bear an impression of the roots of the Nymphæa, which are often three or four inches thick, especially the white-flowered one.]
Her quivering fins and panting gills she hides
But spreads her silver arms upon the tides;
205 Slow as she sails, her ivory neck she laves,
And shakes her golden tresses o'er the waves.
Charm'd round the Nymph, in circling gambols glide
Four Nereid-forms, or shoot along the tide;
Now all as one they rise with frolic spring,
210 And beat the wondering air on humid wing;
Now all descending plunge beneath the main,
And lash the foam with undulating train;
Above, below, they wheel, retreat, advance,
In air and ocean weave the mazy dance;
215 Bow their quick heads, and point their diamond eyes,
And twinkle to the sun with ever-changing dyes.
Where Andes, crested with volcanic beams,
Sheds a long line of light on Plata's streams;
Opes all his springs, unlocks his golden caves,
220 And feeds and freights the immeasurable waves;
Delighted OCYMA at twilight hours
Calls her light car, and leaves the sultry bowers;—
Love's rising ray, and Youth's seductive dye,
Bloom'd on her cheek, and brighten'd in her eye;
225 Chaste, pure, and white, a zone of silver graced
Her tender breast, as white, as pure, as chaste;—-