[_Where oft your Priestley_. l. 166. The fame of Dr. Priestley is known in every part of the earth where science has penetrated. His various discoveries respecting the a.n.a.lysis of the atmosphere, and the production of variety of new airs or ga.s.ses, can only be clearly understood by reading his Experiments on Airs, (3 vols. octavo, Johnson, London.) the following are amongst his many discoveries. 1. The discovery of nitrous and dephlogisticated airs. 2. The exhibition of the acids and alkalies in the form of air. 3. Ascertaining the purity of respirable air by nitrous air. 4. The restoration of vitiated air by vegetation. 5. The influence of light to enable vegetables to yield pure air. 6. The conversion by means of light of animal and vegetable substances, that would otherwise become putrid and offensive, into nourishment of vegetables. 7. The use of respiration by the blood parting with phlogiston, and imbibing dephlogisticated air.
The experiments here alluded to are, 1. Concerning the production of nitrous gas from dissolving iron and many other metals in nitrous acid, which though first discovered by Dr. Hales (Static. Ess. Vol. I. p. 224) was fully investigated, and applied to the important purpose of distinguishing the purity of atmospheric air by Dr. Priestley. When about two measures of common air and one of nitrous gas are mixed together a red effervescence takes place, and the two airs occupy about one fourth less s.p.a.ce than was previously occupied by the common air alone.
2. Concerning the green substance which grows at the bottom of reservoirs of water, which Dr. Priestley discovered to yield much pure air when the sun shone on it. His method of collecting this air is by placing over the green substance, which he believes to be a vegetable of the genus conferva, an inverted bell-gla.s.s previously filled with water, which subsides as the air arises; it has since been found that all vegetables give up pure air from their leaves, when the sun shines upon them, but not in the night, which may be owing to the sleep of the plant.
3. The third refers to the great quant.i.ty of pure air contained in the calces of metals. The calces were long known to weigh much more than the metallic bodies before calcination, insomuch that 100 pounds of lead will produce 112 pounds of minium; the ore of manganese, which is always found near the surface of the earth, is replete with pure air, which is now used for the purpose of bleaching. Other metals when exposed to the atmosphere attract the pure air from it, and become calces by its combination, as zinc, lead, iron; and increase in weight in proportion to the air, which they imbibe.]
"So in Sicilia"s ever-blooming shade When playful PROSERPINE from CERES stray"d, Led with unwary step her virgin trains 180 O"er Etna"s steeps, and Enna"s golden plains; Pluck"d with fair hand the silver-blossom"d bower, And purpled mead,--herself a fairer flower; Sudden, unseen amid the twilight glade, Rush"d gloomy DIS, and seized the trembling maid.-- 185 Her starting damsels sprung from mossy seats, Dropp"d from their gauzy laps the gather"d sweets, Clung round the struggling Nymph, with piercing cries, Pursued the chariot, and invoked the skies;-- Pleased as he grasps her in his iron arms, 190 Frights with soft sighs, with tender words alarms, The wheels descending roll"d in smoky rings, Infernal Cupids flapp"d their demon wings; Earth with deep yawn received the Fair, amaz"d, And far in Night celestial Beauty blaz"d.
[_When playful Proserpine_. l. 178. The fable of Proserpine"s being seized by Pluto as she was gathering flowers, is explained by Lord Bacon to signify the combination or marriage of etherial spirit with earthly materials. Bacon"s Works, Vol. V. p. 470. edit. 4to. Lond. 1778. This allusion is still more curiously exact, from the late discovery of pure air being given up from vegetables, and that then in its unmixed state it more readily combines with metallic or inflammable bodies. From these fables which were probably taken from antient hieroglyphics there is frequently reason to believe that the Egyptians possessed much chemical knowledge, which for want of alphabetical writing perished with their philosophers.]
195 VI. "Led by the Sage, Lo! Britain"s sons shall guide Huge SEA-BALLOONS beneath the tossing tide; The diving castles, roof"d with spheric gla.s.s, Ribb"d with strong oak, and barr"d with bolts of bra.s.s, Buoy"d with pure air shall endless tracks pursue, 200 And PRIESTLEY"S hand the vital flood renew.-- Then shall BRITANNIA rule the wealthy realms, Which Ocean"s wide insatiate wave o"erwhelms; Confine in netted bowers his scaly flocks, Part his blue plains, and people all his rocks.
205 Deep, in warm waves beneath the Line that roll, Beneath the shadowy ice-isles of the Pole, Onward, through bright meandering vales, afar, Obedient Sharks shall trail her sceptred car, With harness"d necks the pearly flood disturb, 210 Stretch the silk rein, and champ the silver curb; Pleased round her triumph wondering Tritons play, And Seamaids hail her on the watery way.
--Oft shall she weep beneath the crystal waves O"er shipwreck"d lovers weltering in their graves; 215 Mingling in death the Brave and Good behold With slaves to glory, and with slaves to gold; Shrin"d in the deep shall DAY and SPALDING mourn, Each in his treacherous bell, sepulchral urn!-- Oft o"er thy lovely daughters, hapless PIERCE!
220 Her sighs shall breathe, her sorrows dew their hea.r.s.e.-- With brow upturn"d to Heaven, "WE WILL NOT PART!"
He cried, and clasp"d them to his aching heart,-- --Dash"d in dread conflict on the rocky grounds, Crash the mock"d masts, the staggering wreck rebounds; 225 Through gaping seams the rushing deluge swims, Chills their pale bosoms, bathes their shuddering limbs, Climbs their white shoulders, buoys their streaming hair, And the last sea-shriek bellows in the air.-- Each with loud sobs her tender sire caress"d, 230 And gasping strain"d him closer to her breast!-- --Stretch"d on one bier they sleep beneath the brine, And their white bones with ivory arms intwine!
[_Led by the Sage_. l. 195. Dr. Priestley"s discovery of the production of pure air from such variety of substances will probably soon be applied to the improvement of the diving bell, as the substances which contain vital air in immense quant.i.ties are of little value as manganese and minium. See additional notes, No. x.x.xIII. In every hundred weight of minium there is combined about twelve pounds of pure air, now as sixty pounds of water are about a cubic foot, and as air is eight hundred times lighter than water, five hundred weight of minium will produce eight hundred cubic feet of air or about six thousand gallons. Now, as this is at least thrice as pure as atmospheric air, a gallon of it may be supposed to serve for three minutes respiration for one man. At present the air can not be set at liberty from minium by vitriolic acid without the application of some heat, this is however very likely soon to be discovered, and will then enable adventurers to journey beneath the ocean in large inverted ships or diving balloons.
Mr. Boyle relates, that Cornelius Drebelle contrived not only a vessel to be rowed under water, but also a liquor to be caried in that vessel, which would supply the want of fresh air. The vessel was made by order of James I. and carried twelve rowers besides pa.s.sengers. It was tried in the river Thames, and one of the persons who was in that submarine voyage told the particulars of the experiments to a person who related them to Mr. Boyle. Annual Register for 1774, p. 248.]
[_Day and Spalding mourn_. l. 217. Mr. Day perished in a diving bell, or diving boat, of his own construction at Plymouth in June 1774, in which he was to have continued for a wager twelve hours one hundred feet deep in water, and probably perished from his not possessing all the hydrostatic knowledge that was necessary. See note on Ulva, Vol. II. of this work. See Annual Register for 1774. p. 245.
Mr. Spalding was professionally ingenious in the art of constructing and managing the diving bell, and had practised the business many years with success. He went down accompanied by one of his young men twice to view the wreck of the Imperial East-Indiaman at the Kish bank in Ireland. On descending the third time in June, 1783, they remained about an hour under water, and had two barrels of air sent down to them, but on the signals from below not being again repeated, after a certain time, they were drawn up by their a.s.sistants and both found dead in the bell.
Annual Register for 1783, p. 206. These two unhappy events may for a time check the ardor of adventurers in traversing the bottom of the ocean, but it is probable in another half century it may be safer to travel under the ocean than over it, since Dr. Priestley"s discovery of procuring pure air in such great abundance from the calces of metals.]
[_Hapless Pierce!_ l, 219. The Haslewell East-Indiaman, outward bound, was wrecked off Seacomb in the isle of Purbec on the 6th of January, 1786; when Capt. Pierce, the commander, with two young ladies, his daughters, and the greatest part of the crew and pa.s.sengers perished in the sea. Some of the officers and about seventy seamen escaped with great difficulty on the rocks, but Capt. Pierce finding it was impossible to save the lives of the young ladies refused to quit the ship, and perished with them.]
"VII. SYLPHS OF NICE EAR! with beating wings you guide The fine vibrations of the aerial tide; 235 Join in sweet cadences the measured words, Or stretch and modulate the trembling cords.
You strung to melody the Grecian lyre, Breathed the rapt song, and fan"d the thought of fire, Or brought in combinations, deep and clear, 240 Immortal harmony to HANDEL"S ear.-- YOU with soft breath attune the vernal gale, When breezy evening broods the listening vale; Or wake the loud tumultuous sounds, that dwell In Echo"s many-toned diurnal sh.e.l.l.
245 YOU melt in dulcet chords, when Zephyr rings The Eolian Harp, and mingle all its strings; Or trill in air the soft symphonious chime, When rapt CECILIA lifts her eye sublime, Swell, as she breathes, her bosoms rising snow, 250 O"er her white teeth in tuneful accents slow, Through her fair lips on whispering pinions move, And form the tender sighs, that kindle love!
"So playful LOVE on Ida"s flowery sides With ribbon-rein the indignant Lion guides; 255 Pleased on his brinded back the lyre he rings, And shakes delirious rapture from the strings; Slow as the pausing Monarch stalks along, Sheaths his retractile claws, and drinks the song; Soft Nymphs on timid step the triumph view, 260 And listening Fawns with beating hoofs pursue; With pointed ears the alarmed forest starts, And Love and Music soften savage hearts.
[_Indignant lion guides_. l. 254. Described from an antient gem, expressive of the combined power of love and music, in the Museum Florent.]
VIII. "SYLPHS! YOUR bold hosts, when Heaven with justice dread Calls the red tempest round the guilty head, 265 Fierce at his nod a.s.sume vindictive forms, And launch from airy cars the vollied storms.-- From Ashur"s vales when proud SENACHERIB trod, Pour"d his swoln heart, defied the living G.o.d, Urged with incessant shouts his glittering powers; 270 And JUDAH shook through all her ma.s.sy towers; Round her sad altars press"d the prostrate crowd, Hosts beat their b.r.e.a.s.t.s, and suppliant chieftains bow"d; Loud shrieks of matrons thrill"d the troubled air, And trembling virgins rent their scatter"d hair; 275 High in the midst the kneeling King adored, Spread the blaspheming scroll before the Lord, Raised his pale hands, and breathed his pausing sighs, And fixed on Heaven his dim imploring eyes,-- "Oh! MIGHTY G.o.d! amidst thy Seraph-throng 280 "Who sit"st sublime, the Judge of Right and Wrong; "Thine the wide earth, bright sun, and starry zone, "That twinkling journey round thy golden throne; "Thine is the crystal source of life and light, "And thine the realms of Death"s eternal night.
285 "Oh, bend thine ear, thy gracious eye incline, "Lo! Ashur"s King blasphemes thy holy shrine, "Insults our offerings, and derides our vows,--- "Oh! strike the diadem from his impious brows, "Tear from his murderous hand the b.l.o.o.d.y rod, 290 "And teach the trembling nations, "THOU ART G.o.d!"-- --SYLPHS! in what dread array with pennons broad Onward ye floated o"er the ethereal road, Call"d each dank steam the reeking marsh exhales, Contagious vapours, and volcanic gales, 295 Gave the soft South with poisonous breath to blow, And rolled the dreadful whirlwind on the foe!-- Hark! o"er the camp the venom"d tempest sings, Man falls on Man, on buckler buckler rings; Groan answers groan, to anguish anguish yields, 300 And DEATH"S loud accents shake the tented fields!
--High rears the Fiend his grinning jaws, and wide Spans the pale nations with colossal stride, Waves his broad falchion with uplifted hand, And his vast shadow darkens all the land.
[_Volcanic gales_. l. 294. The pestilential winds of the east are described by various authors under various denominations; as harmattan, samiel, samium, syrocca, kamsin, seravansum. M. de Beauchamp describes a remarkable south wind in the deserts about Bagdad, called seravansum, or poison-wind; it burns the face, impedes respiration, strips the trees of their leaves, and is said to pa.s.s on in a streight line, and often kills people in six hours. P. Cotte sur la Meteorol. a.n.a.lytical Review for February, 1790. M. Volney says, the hot wind or ramsin seems to blow at the season when the sands of the deserts are the hottest; the air is then filled with an extreamly subtle dust. Vol. I. p. 61. These winds blow in all directions from the deserts; in Egypt the most violent proceed from the S.S.W. at Mecca from the E. at Surat from the N. at Ba.s.sora from the N.W. at Bagdad from the W. and in Syria from the S.E.
On the south of Syria, he adds, where the Jordan flows is a country of volcanos; and it is observed that the earthquakes in Syria happen after their rainy season, which is also conformable to a similar observation made by Dr. Shaw in Barbary. Travels in Egypt, Vol. I. p. 303.
These winds seem all to be of volcanic origin, as before mentioned, with this difference, that the Simoom is attended with a stream of electric matter; they seem to be in consequence of earthquakes caused by the monsoon floods, which fall on volcanic fires in Syria, at the same time that they inundate the Nile.]
305 IX. 1. "Ethereal cohorts! Essences of Air!
Make the green children of the Spring your care!
Oh, SYLPHS! disclose in this inquiring age One GOLDEN SECRET to some favour"d sage; Grant the charm"d talisman, the chain, that binds, 310 Or guides the changeful pinions of the winds!
--No more shall h.o.a.ry Boreas, issuing forth With Eurus, lead the tempests of the North; Rime the pale Dawn, or veil"d in flaky showers Chill the sweet bosoms of the smiling Hours.
315 By whispering Auster waked shall Zephyr rise, Meet with soft kiss, and mingle in the skies, Fan the gay floret, bend the yellow ear, And rock the uncurtain"d cradle of the year; Autumn and Spring in lively union blend, 320 And from the skies the Golden Age descend.
[_One golden secret_. l. 308. The suddenness of the change of the wind from N.E. to S.W. seems to shew that it depends on some minute chemical cause; which if it was discovered might probably, like other chemical causes, be governed by human agency; such as blowing up rocks by gunpowder, or extracting the lightening from the clouds. If this could be accomplished, it would be the most happy discovery that ever has happened to these northern lat.i.tudes, since in this country the N.E.
winds bring frost, and the S.W. ones are attended with warmth and moisture; if the inferior currents of air could be kept perpetually from the S.W. supplied by new productions of air at the line, or by superior currents flowing in a contrary direction, the vegetation of this country would be doubled; as in the moist vallies of Africa, which know no frost; the number of its inhabitants would be increased, and their lives prolonged; as great abundance of the aged and infirm of mankind, as well as many birds and animals, are destroyed by severe continued frosts in this climate.]
2. "Castled on ice, beneath the circling Bear, A vast CAMELION spits and swallows air; O"er twelve degrees his ribs gigantic bend, And many a league his leathern jaws extend; 325 Half-fish, beneath, his scaly volutes spread, And vegetable plumage crests his head; Huge fields of air his wrinkled skin receives, From panting gills, wide lungs, and waving leaves; Then with dread throes subsides his bloated form, 330 His shriek the thunder, and his sigh the storm.
Oft high in heaven the hissing Demon wins His towering course, upborne on winnowing fins; Steers with expanded eye and gaping mouth, His ma.s.s enormous to the affrighted South; 335 Spreads o"er the shuddering Line his shadowy limbs, And Frost and Famine follow as he swims.-- SYLPHS! round his cloud-built couch your bands array, And mould the Monster to your gentle sway; Charm with soft tones, with tender touches check, 340 Bend to your golden yoke his willing neck, With silver curb his yielding teeth restrain, And give to KIRWAN"S hand the silken rein.
--Pleased shall the Sage, the dragon-wings between, Bend o"er discordant climes his eye serene, 345 With Lapland breezes cool Arabian vales, And call to Hindostan antarctic gales, Adorn with wreathed ears Kampschatca"s brows, And scatter roses on Zealandic snows, Earth"s wondering Zones the genial seasons share, 350 And nations hail him "MONARCH OF THE AIR."
[_A vast Camelion_. l. 322. See additional notes, No. x.x.xIII. on the destruction and reproduction of the atmosphere.]
[_To Kirwan"s hand_. l. 342. Mr. Kirwan has published a valuable treatise on the temperature of climates, as a step towards investigating the theory of the winds; and has since written some ingenious papers on this subject in the Transactions of the Royal Irish Society.]
X. 1. "SYLPHS! as you hover on ethereal wing, Brood the green children of parturient Spring!-- Where in their bursting cells my Embryons rest, I charge you guard the vegetable nest; 355 Count with nice eye the myriad SEEDS, that swell Each vaulted womb of husk, or pod, or sh.e.l.l; Feed with sweet juices, clothe with downy hair, Or hang, inshrined, their little orbs in air.
[_The myriad seeds_. l. 355. Nature would seem to have been wonderfully prodigal in the seeds of vegetables, and the sp.a.w.n of fish; almost any one plant, if all its seeds should grow to maturity, would in a few years alone people the terrestrial globe. Mr. Ray a.s.serts that 101 seeds of tobacco weighed only one grain, and that from one tobacco plant the seeds thus calculated amounted to 360,000! The seeds of the ferns are by him supposed to exceed a million on a leaf. As the works of nature are governed by general laws this exuberant reproduction prevents the accidental extinction of the species, at the same time that they serve for food for the higher orders of animation.
Every seed possesses a reservoir of nutriment designed for the growth of the future plant, this consists of starch, mucilage, or oil, within the coat of the seed, or of sugar and subacid pulp in the fruits, which belongs to it.
For the preservation of the immature seed nature has used many ingenious methods; some are wrapped in down, as the seeds of the rose, bean, and cotton-plant; others are suspended in a large air-vessel, as those of the bladder-sena, staphylaea, and pea.]
"So, late descry"d by HERSCHEL"S piercing sight, 360 Hang the bright squadrons of the twinkling Night; Ten thousand marshall"d stars, a silver zone, Effuse their blended l.u.s.tres round her throne; Suns call to suns, in lucid clouds conspire, And light exterior skies with golden fire; 365 Resistless rolls the illimitable sphere, And one great circle forms the unmeasured year.
--Roll on, YE STARS! exult in youthful prime, Mark with bright curves the printless steps of Time; Near and more near your beamy cars approach, 370 And lessening orbs on lessening orbs encroach;-- Flowers of the sky! ye too to age must yield, Frail as your silken sisters of the field!
Star after star from Heaven"s high arch shall rush, Suns sink on suns, and systems systems crush, 375 Headlong, extinct, to one dark centre fall, And Death and Night and Chaos mingle all!
--Till o"er the wreck, emerging from the storm, Immortal NATURE lifts her changeful form, Mounts from her funeral pyre on wings of flame, 380 And soars and shines, another and the same.
[_And light exterior_. l. 364. I suspect this line is from Dwight"s Conquest of Canaan, a poem written by a very young man, and which contains much fine versification.]
[_Near and more near_. l. 369. From the vacant s.p.a.ces in some parts of the heavens, and the correspondent cl.u.s.ters of stars in their vicinity, Mr. Herschel concludes that the nebulae or constellations of fixed stars are approaching each other, and must finally coalesce in one ma.s.s. Phil.
Trans. Vol. LXXV.]
[_Till o"er the wreck_. l. 377. The story of the phenix rising from its own ashes with a twinkling star upon its head, seems to have been an antient hieroglyphic emblem of the destruction and resuscitation of all things.