Volume I Part 13 (1/2)
[_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 distinguis.h.i.+ng 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 s.h.i.+nes 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 s.h.i.+pwreck'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 rus.h.i.+ng 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 s.h.i.+ps 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 s.h.i.+p, 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.