The Botanic Garden

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THE
ECONOMY OF VEGETATION.

CANTO IV.

As when at noon in Hybla's fragrant bowers
CACALIA opens all her honey'd flowers;
Contending swarms on bending branches cling,
And nations hover on aurelian wing;
5 So round the GODDESS, ere she speaks, on high
Impatient SYLPHS in gawdy circlets fly;
Quivering in air their painted plumes expand,
And coloured shadows dance upon the land.

[_Cacalia opens_. l. 2. The importance of the nectarium or honey-gland
in the vegetable economy is seen from the very complicated apparatus,
which nature has formed in some flowers for the preservation of their
honey from insects, as in the aconites or monkshoods; in other plants
instead of a great apparatus for its protection a greater secretion of
it is produced that thence a part may be spared to the depredation of
insects. The cacalia suaveolens produces so much honey that on some days
it may be smelt at a great distance from the plant. I remember once
counting on one of these plants besides bees of various kinds without
number, above two hundred painted butterflies, which gave it the
beautiful appearance of being covered with additional flowers.]

I. "SYLPHS! YOUR light troops the tropic Winds confine,
10 And guide their streaming arrows to the Line;
While in warm floods ecliptic breezes rise,
And sink with wings benumb'd in colder skies.
You bid Monsoons on Indian seas reside,
And veer, as moves the sun, their airy tide;
15 While southern gales o'er western oceans roll,
And Eurus steals his ice-winds from the Pole.
Your playful trains, on sultry islands born,
Turn on fantastic toe at eve and morn;
With soft susurrant voice alternate sweep
20 Earth's green pavilions and encircling deep.
OR in itinerant cohorts, borne sublime
On tides of ether, float from clime to clime;
O'er waving Autumn bend your airy ring,
Or waft the fragrant bosom of the Spring.

[_The tropic winds_. l. 9. See additional notes, No. XXXIII.]

25 II. "When Morn, escorted by the dancing Hours,
O'er the bright plains her dewy lustre showers;
Till from her sable chariot Eve serene
Drops the dark curtain o'er the brilliant scene;
You form with chemic hands the airy surge,
30 Mix with broad vans, with shadowy tridents urge.
SYLPHS! from each sun-bright leaf, that twinkling shakes
O'er Earth's green lap, or shoots amid her lakes,
Your playful bands with simpering lips invite,
And wed the enamour'd OXYGENE to LIGHT.--
35 Round their white necks with fingers interwove,
Cling the fond Pair with unabating love;
Hand link'd in hand on buoyant step they rise,
And soar and glisten in unclouded skies.
Whence in bright floods the VITAL AIR expands,
40 And with concentric spheres involves the lands;
Pervades the swarming seas, and heaving earths,
Where teeming Nature broods her myriad births;
Fills the fine lungs of all that _breathe_ or _bud_,
Warms the new heart, and dyes the gushing blood;
45 With Life's first spark inspires the organic frame,
And, as it wastes, renews the subtile flame.

[_The enamour'd oxygene_. l. 34. The common air of the atmosphere
appears by the analysis of Dr. Priestley and other philosophers to
consist of about three parts of an elastic fluid unfit for respiration
or combustion, called azote by the French school, and about one fourth
of pure vital air fit for the support of animal life and of combustion,
called oxygene. The principal source of the azote is probably from the
decomposition of all vegetable and animal matters by putrefaction and
combustion; the principal source of vital air or oxygene is perhaps from
the decomposition of water in the organs of vegetables by means of the
sun's light. The difficulty of injecting vegetable vessels seems to shew
that their perspirative pores are much less than those of animals, and
that the water which constitutes their perspiration is so divided at the
time of its exclusion that by means of the sun's light it becomes
decomposed, the inflammable air or hydrogene, which is one of its
constituent parts, being retained to form the oil, resin, wax, honey,
&c. of the vegetable economy; and the other part, which united with
light or heat becomes vital air or oxygene gas, rises into the
atmosphere and replenishes it with the food of life.

Dr. Priestley has evinced by very ingenious experiments that the blood
gives out phlogiston, and receives vital air, or oxygene-gas by the
lungs. And Dr. Crawford has shewn that the blood acquires heat from this
vital air in respiration. There is however still a something more subtil
than heat, which must be obtained in respiration from the vital air, a
something which life can not exist a few minutes without, which seems
necessary to the vegetable as well as to the animal world, and which as
no organized vessels can confine it, requires perpetually to be renewed.
See note on Canto I. l. 401.]

"So pure, so soft, with sweet attraction shone
Fair PSYCHE, kneeling at the ethereal throne;
Won with coy smiles the admiring court of Jove,
50 And warm'd the bosom of unconquer'd LOVE.--
Beneath a moving shade of fruits and flowers
Onward they march to HYMEN'S sacred bowers;
With lifted torch he lights the festive train,
Sublime, and leads them in his golden chain;
55 Joins the fond pair, indulgent to their vows,
And hides with mystic veil their blushing brows.
Round their fair forms their mingling arms they fling,
Meet with warm lip, and clasp with rustling wing.--
--Hence plastic Nature, as Oblivion whelms
60 Her fading forms, repeoples all her realms;
Soft Joys disport on purple plumes unfurl'd,
And Love and Beauty rule the willing world.

[_Fair Psyche_. l. 48. Described from an antient gem on a fine onyx in
possession of the Duke of Marlborough, of which there is a beautiful
print in Bryant's Mythol. Vol II. p. 392. And from another antient gem
of Cupid and Psyche embracing, of which there is a print in Spence's
Polymetis. p. 82.]

[_Repeoples all her realms_. l. 60.

Quae mare navigerum et terras frugiferentes
Concelebras; per te quoniam genus omne animantum
Concipitur, visitque exortum lumina folis. Lucret.]

III. 1. "SYLPHS! Your bold myriads on the withering heath
Stay the fell SYROC'S suffocative breath;
65 Arrest SIMOOM in his realms of sand,
The poisoned javelin balanced in his hand;--
Fierce on blue streams he rides the tainted air,
Points his keen eye, and waves his whistling hair;
While, as he turns, the undulating soil
70 Rolls in red waves, and billowy deserts boil.

[_Arrest Simoom_. l. 65. "At eleven o'clock while we were with great
pleasure contemplating the rugged tops of Chiggre, where we expected to
solace ourselves with plenty of good water, Idris cried out with a loud
voice, "fall upon your faces, for here is the simoom!" I saw from the
S.E. a haze come in colour like the purple part of a rainbow, but not so
compressed or thick; it did not occupy twenty yards in breadth, and was
about twelve feet high from the ground. It was a kind of a blush upon
the air, and it moved very rapidly, for I scarce could turn to fall upon
the ground with my head to the northward, when I felt the heat of its
current plainly upon my face. We all lay flat upon the ground, as if
dead, till Idris told us it was blown over. The meteor, or purple haze,
which I saw was indeed passed; but the light air that still blew was of
heat to threaten suffocation. For my part I found distinctly in my
breast, that I had imbibed a part of it; nor was I free of an asthmatic
sensation till I had been some months in Italy." Bruce's Travels. Vol.
IV. p. 557.

It is difficult to account for the narrow track of this pestilential
wind, which is said not to exceed twenty yards, and for its small
elevation of twelve feet. A whirlwind will pass forwards, and throw down
an avenue of trees by its quick revolution as it passes, but nothing
like a whirling is described as happening in these narrow streams of
air, and whirlwinds ascend to greater heights. There seems but one known
manner in which this channel of air could be effected, and that is by
electricity.

The volcanic origin of these winds is mentioned in the note on Chunda in
Vol. II. of this work; it must here be added, that Professor Vairo at
Naples found, that during the eruption of Vesuvius perpendicular iron
bars were electric; and others have observed suffocating damps to attend
these eruptions. Ferber's Travels in Italy, p. 133. And lastly, that a
current of air attends the passage of electric matter, as is seen in
presenting an electrized point to the flame of a candle. In Mr. Bruce's
account of this simoom, it was in its course over a quite dry desert of
sand, (and which was in consequence unable to conduct an electric stream
into the earth beneath it,) to some moist rocks at but a few miles
distance; and thence would appear to be a stream of electricity from a
volcano attended with noxious air; and as the bodies of Mr. Bruce and
his attendants were insulated on the sand, they would not be sensible of
their increased electricity, as it passed over them; to which it may be
added, that a sulphurous or suffocating sensation is said to accompany
flames of lightning, and even strong sparks of artificial electricity.
In the above account of the simoom, a great redness in the air is said
to be a certain sign of its approach, which may be occasioned by the
eruption of flame from a distant volcano in these extensive and
impenetrable deserts of sand. See Note on l. 294 of this Canto.]

You seize TORNADO by his locks of mist,
Burst his dense clouds, his wheeling spires untwist;
Wide o'er the West when borne on headlong gales,
Dark as meridian night, the Monster sails,
75 Howls high in air, and shakes his curled brow,
Lashing with serpent-train the waves below,
Whirls his black arm, the forked lightning flings,
And showers a deluge from his demon-wings.

[_Tornado's_. l. 71. See additional notes, No. XXXIII.]

2. "SYLPHS! with light shafts YOU pierce the drowsy FOG,
80 That lingering slumbers on the sedge-wove bog,
With webbed feet o'er midnight meadows creeps,
Or flings his hairy limbs on stagnant deeps.
YOU meet CONTAGION issuing from afar,
And dash the baleful conqueror from his car;
85 When, Guest of DEATH! from charnel vaults he steals,
And bathes in human gore his armed wheels.

[_On stagnant deeps_. l. 82. All contagious miasmata originate either
from animal bodies, as those of the small pox, or from putrid morasses;
these latter produce agues in the colder climates, and malignant fevers
in the warmer ones. The volcanic vapours which cause epidemic coughs,
are to be ranked amongst poisons, rather than amongst the miasmata,
which produce contagious diseases.]

"Thus when the PLAGUE, upborne on Belgian air,
Look'd through the mist and shook his clotted hair,
O'er shrinking nations steer'd malignant clouds,
90 And rain'd destruction on the gasping crouds.
The beauteous AEGLE felt the venom'd dart,
Slow roll'd her eye, and feebly throbb'd her heart;
Each fervid sigh seem'd shorter than the last,
And starting Friendship shunn'd her, as she pass'd.
95 --With weak unsteady step the fainting Maid
Seeks the cold garden's solitary shade,
Sinks on the pillowy moss her drooping head,
And prints with lifeless limbs her leafy bed.
--On wings of Love her plighted Swain pursues,
100 Shades her from winds, and shelters her from dews,
Extends on tapering poles the canvas roof,
Spreads o'er the straw-wove matt the flaxen woof,
Sweet buds and blossoms on her bolster strows,
And binds his kerchief round her aching brows;
105 Sooths with soft kiss, with tender accents charms,
And clasps the bright Infection in his arms.--
With pale and languid smiles the grateful Fair
Applauds his virtues, and rewards his care;
Mourns with wet cheek her fair companions fled
110 On timorous step, or number'd with the dead;
Calls to its bosom all its scatter'd rays,
And pours on THYRSIS the collected blaze;
Braves the chill night, caressing and caress'd,
And folds her Hero-lover to her breast.--
115 Less bold, LEANDER at the dusky hour
Eyed, as he swam, the far love-lighted tower;
Breasted with struggling arms the tossing wave,
And sunk benighted in the watery grave.
Less bold, TOBIAS claim'd the nuptial bed,
120 Where seven fond Lovers by a Fiend had bled;
And drove, instructed by his Angel-Guide,
The enamour'd Demon from the fatal bride.--
--SYLPHS! while your winnowing pinions fan'd the air,
And shed gay visions o'er the sleeping pair;
125 LOVE round their couch effused his rosy breath,
And with his keener arrows conquer'd DEATH.

[_The beauteous Aegle_. l. 91. When the plague raged in Holland in 1636,
a young girl was seized with it, had three carbuncles, and was removed
to a garden, where her lover, who was betrothed to her, attended her as
a nurse, and slept with her as his wife. He remained uninfected, and she
recovered, and was married to him. The story is related by Vinc.
Fabricius in the Misc. Cur. Ann. II. Obs. 188.]

IV. 1. "You charm'd, indulgent SYLPHS! their learned toil,
And crown'd with fame your TORRICELL, and BOYLE;
Taught with sweet smiles, responsive to their prayer,
130 The spring and pressure of the viewless air.
--How up exhausted tubes bright currents flow
Of liquid silver from the lake below,
Weigh the long column of the incumbent skies,
And with the changeful moment fall and rise.
135 --How, as in brazen pumps the pistons move,
The membrane-valve sustains the weight above;
Stroke follows stroke, the gelid vapour falls,
And misty dew-drops dim the crystal walls;
Rare and more rare expands the fluid thin,
140 And Silence dwells with Vacancy within.--
So in the mighty Void with grim delight
Primeval Silence reign'd with ancient Night.

[_Torricell and Boyle_. l. 128. The pressure of the atmosphere was
discovered by Torricelli, a disciple of Galileo, who had previously
found that the air had weight. Dr. Hook and M. Du Hamel ascribe the
invention of the air-pump to Mr. Boyle, who however confesses he had
some hints concerning its construction from De Guerick. The vacancy at
the summit of the barometer is termed the Torricellian vacuum, and the
exhausted receiver of an air pump the Boylean vacuum, in honour of these
two philosophers.

The mist and descending dew which appear at first exhausting the
receiver of an air-pump, are explained in the Phil. Trans. Vol. LXXVIII.
from the cold produced by the expansion of air. For a thermometer placed
in the receiver sinks some degrees, and in a very little time, as soon
as a sufficient quantity of heat can be acquired from the surrounding
bodies, the dew becomes again taken up. See additional notes, No. VII.
Mr. Saussure observed on placing his hygrometer in a receiver of an air-
pump, that though on beginning to exhaust it the air became misty, and
parted with its moisture, yet the hair of his hygrometer contracted, and
the instrument pointed to greater dryness. This unexpected occurrence is
explained by M. Monge (Annales de Chymie, Tom. V.) to depend on the want
of the usual pressure of the atmosphere to force the aqueous particles
into the pores of the hair; and M. Saussure supposes, that his vesicular
vapour requires more time to be redissolved, than is necessary to dry
the hair of his thermometer. Essais sur l'Hygrom. p. 226. but I suspect
there is a less hypothetical way of understanding it; when a colder body
is brought into warm and moist air, (as a bottle of spring-water for
instance,) a steam is quickly collected on its surface; the contrary
occurs when a warmer body is brought into cold and damp air, it
continues free from dew so long as it continues warm; for it warms the
atmosphere around it, and renders it capable of receiving instead of
parting with moisture. The moment the air becomes rarefied in the
receiver of the air-pump it becomes colder, as appears by the
thermometer, and deposits its vapour; but the hair of Mr. Saussure's
hygrometer is now warmer than the air in which it is immersed, and in
consequence becomes dryer than before, by warming the air which
immediately surrounds it, a part of its moisture evaporating along with
its heat.]

2. "SYLPHS! your soft voices, whispering from the skies,
Bade from low earth the bold MONGULFIER rise;
145 Outstretch'd his buoyant ball with airy spring,
And bore the Sage on levity of wing;--
Where were ye, SYLPHS! when on the ethereal main
Young ROSIERE launch'd, and call'd your aid in vain?
Fair mounts the light balloon, by Zephyr driven,
150 Parts the thin clouds, and sails along the heaven;
Higher and yet higher the expanding bubble flies,
Lights with quick flash, and bursts amid the skies.--
Headlong He rushes through the affrighted air
With limbs distorted, and dishevel'd hair,
155 Whirls round and round, the flying croud alarms,
And DEATH receives him in his sable arms!--
So erst with melting wax and loosen'd strings
Sunk hapless ICARUS on unfaithful wings;
His scatter'd plumage danced upon the wave,
160 And sorrowing Mermaids deck'd his watery grave;
O'er his pale corse their pearly sea-flowers shed,
And strew'd with crimson moss his marble bed;
Struck in their coral towers the pausing bell,
And wide in ocean toll'd his echoing knell.

[_Young Rosiere launch'd_. l. 148. M. Pilatre du Rosiere with a M.
Romain rose in a balloon from Boulogne in June 1785, and after having
been about a mile high for about half an hour the balloon took fire, and
the two adventurers were dashed to pieces on their fall to the ground.
Mr. Rosiere was a philosopher of great talents and activity, joined with
such urbanity and elegance of manners, as conciliated the affections of
his acquaintance and rendered his misfortune universally lamented.
Annual Register for 1784 and 1785, p. 329.]

[_And wide in ocean_. l. 164. Denser bodies propagate vibration or sound
better than rarer ones; if two stones be struck together under the
water, they may be heard a mile or two by any one whose head is immersed
at that distance, according to an experiment of Dr. Franklin. If the ear
be applied to one end of a long beam of timber, the stroke of a pin at
the other end becomes sensible; if a poker be suspended in the middle of
a garter, each end of which is pressed against the ear, the least
percussions on the poker give great sounds. And I am informed by laying
the ear on the ground the tread of a horse may be discerned at a great
distance in the night. The organs of hearing belonging to fish are for
this reason much less complicated than of quadrupeds, as the fluid they
are immersed in so much better conveys its vibrations. And it is
probable that some shell-fish which have twisted shells like the cochlea
and semicircular canals of the ears of men and quadrupeds may have no
appropriated organ for perceiving the vibrations of the element they
live in, but may by their spiral form be in a manner all ear.]

165 V. "SYLPHS! YOU, retiring to sequester'd bowers,
Where oft your PRIESTLEY woos your airy powers,
On noiseless step or quivering pinion glide,
As sits the Sage with Science by his side;
To his charm'd eye in gay undress appear,
170 Or pour your secrets on his raptured ear.
How nitrous Gas from iron ingots driven
Drinks with red lips the purest breath of heaven;
How, while Conferva from its tender hair
Gives in bright bubbles empyrean air;
175 The crystal floods phlogistic ores calcine,
And the pure ETHER marries with the MINE.

[_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 analysis of the atmosphere, and the
production of variety of new airs or gasses, 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 space 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-glass 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 quantity 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 glass,
Ribb'd with strong oak, and barr'd with bolts of brass,
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 hearse.--
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!

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