The Botanic Garden

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[_Alarm with Comet-blaze_. l. 133. See additional notes, No. IV.]

[_The Sun's phlogistic orb_. l. 136. See additional notes, No. V.]

III. NYMPHS! YOUR fine forms with steps impassive mock
Earth's vaulted roofs of adamantine rock;
Round her still centre tread the burning soil,
140 And watch the billowy Lavas, as they boil;
Where, in basaltic caves imprison'd deep,
Reluctant fires in dread suspension sleep;
Or sphere on sphere in widening waves expand,
And glad with genial warmth the incumbent land.
145 So when the Mother-bird selects their food
With curious bill, and feeds her callow brood;
Warmth from her tender heart eternal springs,
And pleased she clasps them with extended wings.

[_Round the still centre_. l. 139. Many philosophers have believed that
the central parts of the earth consist of a fluid mass of burning lava,
which they have called a subterraneous sun; and have supposed, that it
contributes to the production of metals, and to the growth of
vegetables. See additional notes, No. VI.]

[_Or sphere on sphere_. l. 143. See additional notes, No. VII.]

"YOU from deep cauldrons and unmeasured caves
150 Blow flaming airs, or pour vitrescent waves;
O'er shining oceans ray volcanic light,
Or hurl innocuous embers to the night.--
While with loud shouts to Etna Heccla calls,
And Andes answers from his beacon'd walls;
155 Sea-wilder'd crews the mountain-stars admire,
And Beauty beams amid tremendous fire.

[_Hurl innocuous embers_. l. 152. The immediate cause of volcanic
eruptions is believed to be owing to the water of the sea, or from
lakes, or inundations, finding itself a passage into the subterraneous
fires, which may lie at great depths. This must first produce by its
coldness a condensation of the vapour there existing, or a vacuum, and
thus occasion parts of the earth's crust or shell to be forced down by
the pressure of the incumbent atmosphere. Afterwards the water being
suddenly raised into steam produces all the explosive effects of
earthquakes. And by new accessions of water during the intervals of the
explosions the repetition of the shocks is caused. These circumstances
were hourly illustrated by the fountains of boiling water in Iceland, in
which the surface of the water in the boiling wells sunk down low before
every new ebullition.

Besides these eruptions occasioned by the steam of water, there seems to
be a perpetual effusion of other vapours, more noxious and (as far as it
is yet known) perhaps greatly more expansile than water from the
Volcanos in various parts of the world. As these Volcanos are supposed
to be spiracula or breathing holes to the great subterraneous fires, it
is probable that the escape of elastic vapours from them is the cause,
that the earthquakes of modern days are of such small extent compared to
those of antient times, of which vestiges remain in every part of the
world, and on this account may be said not only to be innocuous, but
useful.]

"Thus when of old, as mystic bards presume,
Huge CYCLOPS dwelt in Etna's rocky womb,
On thundering anvils rung their loud alarms,
160 And leagued with VULCAN forged immortal arms;
Descending VENUS sought the dark abode,
And sooth'd the labours of the grisly God.--
While frowning Loves the threatening falchion wield,
And tittering Graces peep behind the shield,
165 With jointed mail their fairy limbs o'erwhelm,
Or nod with pausing step the plumed helm;
With radiant eye She view'd the boiling ore,
Heard undismay'd the breathing bellows roar,
Admired their sinewy arms, and shoulders bare,
170 And ponderous hammers lifted high in air,
With smiles celestial bless'd their dazzled sight,
And Beauty blazed amid infernal night.

IV. "EFFULGENT MAIDS! YOU round deciduous day,
Tressed with soft beams, your glittering bands array;
175 On Earth's cold bosom, as the Sun retires,
Confine with folds of air the lingering fires;
O'er Eve's pale forms diffuse phosphoric light,
And deck with lambent flames the shrine of Night.
So, warm'd and kindled by meridian skies,
180 And view'd in darkness with dilated eyes,
BOLOGNA'S chalks with faint ignition blaze,
BECCARI'S shells emit prismatic rays.
So to the sacred Sun in MEMNON's fane,
Spontaneous concords quired the matin strain;
185 --Touch'd by his orient beam, responsive rings
The living lyre, and vibrates all it's strings;
Accordant ailes the tender tones prolong,
And holy echoes swell the adoring song.

[_Confine with folds of air_. l. 176. The air, like all other bad
conductors of electricity, is known to be a bad conductor of heat; and
thence prevents the heat acquired from the sun's rays by the earth's
surface from being so soon dissipated, in the same manner as a blanket,
which may be considered as a sponge filled with air, prevents the escape
of heat from the person wrapped in it. This seems to be one cause of the
great degree of cold on the tops of mountains, where the rarity of the
air is greater, and it therefore becomes a better conductor both of heat
and electricity. See note on Barometz, Vol. II. of this work.

There is however another cause to which the great coldness of mountains
and of the higher regions of the atmosphere is more immediately to be
ascribed, explained by Dr. Darwin in the Philos. Trans. Vol. LXXVIII.
who has there proved by experiments with the air-gun and air-pump, that
when any portion of the atmosphere becomes mechanically expanded, it
absorbs heat from the bodies in its vicinity. And as the air which
creeps along the plains, expands itself by a part of the pressure being
taken off when it ascends the sides of mountains; it at the same time
attracts heat from the summits of those mountains, or other bodies which
happen to be immersed in it, and thus produces cold. Hence he concludes
that the hot air at the bottom of the Andes becomes temperate by its own
rarefaction when it ascends to the city of Quito; and by its further
rarefaction becomes cooled to the freezing point when it ascends to the
snowy regions on the summits of those mountains. To this also he
attributes the great degree of cold experienced by the aeronauts in
their balloons; and which produces hail in summer at the height of only
two or three miles in the atmosphere.]

[_Diffuse phosphoric light_. l. 177. I have often been induced to
believe from observation, that the twilight of the evenings is lighter
than that of the mornings at the same distance from noon. Some may
ascribe this to the greater height of the atmosphere in the evenings
having been rarefied by the sun during the day; but as its density must
at the same time be diminished, its power of refraction would continue
the same. I should rather suppose that it may be owing to the
phosphorescent quality (as it is called) of almost all bodies; that is,
when they have been exposed to the sun they continue to emit light for a
considerable time afterwards. This is generally believed to arise either
from such bodies giving out the light which they had previously
absorbed; or to the continuance of a slow combustion which the light
they had been previously exposed to had excited. See the next note.]

[_Beccari's shells_. l. 182. Beccari made many curious experiments on
the phosphoric light, as it is called, which becomes visible on bodies
brought into a dark room, after having been previously exposed to the
sunshine. It appears from these experiments, that almost all inflammable
bodies possess this quality in a greater or less degree; white paper or
linen thus examined after having been exposed to the sunshine, is
luminous to an extraordinary degree; and if a person shut up in a dark
room, puts one of his hands out into the sun's light for a short time
and then retracts it, he will be able to see that hand distinctly and
not the other. These experiments seem to countenance the idea of light
being absorbed and again emitted from bodies when they are removed into
darkness. But Beccari further pretended, that some calcareous
compositions when exposed to red, yellow, or blue light, through
coloured glasses, would on their being brought into a dark room emit
coloured lights. This mistaken fact of Beccari's, Mr. Wilson decidedly
refutes; and among many other curious experiments discovered, that if
oyster-shells were thrown into a common fire and calcined for about half
an hour, and then brought to a person who had previously been some
minutes in a dark room, that many of them would exhibit beautiful irises
of prismatic colours, from whence probably arose Beccari's mistake. Mr.
Wilson from hence contends, that these kinds of phosphori do not emit
the light they had previously received, but that they are set on fire by
the sun's rays, and continue for some time a slow combustion after they
are withdrawn from the light. Wilson's Experiments on Phosphori.
Dodsley, 1775.

The Bolognian stone is a selenite, or gypsum, and has been long
celebrated for its phosphorescent quality after having been burnt in a
sulphurous fire; and exposed when cold to the sun's light. It may be
thus well imitated: Calcine oyster-shells half an hour, pulverize them
when cold, and add one third part of flowers of sulphur, press them
close into a small crucible, and calcine them for an hour or longer, and
keep the powder in a phial close stopped. A part of this powder is to be
exposed for a minute or two to the sunbeams, and then brought into a
dark room. The calcined Bolognian stone becomes a calcareous hepar of
sulphur; but the calcined shells, as they contain the animal acid, may
also contain some of the phosphorus of Kunkel.]

[_In Memnon's fane_. l. 183. See additional notes. No. VIII.]

"YOU with light Gas the lamps nocturnal feed,
190 Which dance and glimmer o'er the marshy mead;
Shine round Calendula at twilight hours,
And tip with silver all her saffron flowers;
Warm on her mossy couch the radiant Worm,
Guard from cold dews her love-illumin'd form,
195 From leaf to leaf conduct the virgin light,
Star of the earth, and diamond of the night.
You bid in air the tropic Beetle burn,
And fill with golden flame his winged urn;
Or gild the surge with insect-sparks, that swarm
200 Round the bright oar, the kindling prow alarm;
Or arm in waves, electric in his ire,
The dread Gymnotus with ethereal fire.--
Onward his course with waving tail he helms,
And mimic lightenings scare the watery realms,
205 So, when with bristling plumes the Bird of JOVE
Vindictive leaves the argent fields above,
Borne on broad wings the guilty world he awes,
And grasps the lightening in his shining claws.

[_The lamps nocturnal_. l. 189. The ignis fatuus or Jack a lantern,
frequently alluded to by poets, is supposed to originate from the
inflammable air, or Hydrogene, given up from morasses; which being of a
heavier kind from its impurity than that obtained from iron and water,
hovers near the surface of the earth, and uniting with common air gives
out light by its slow ignition. Perhaps such lights have no existence,
and the reflection of a star on watery ground may have deceived the
travellers, who have been said to be bewildered by them? if the fact was
established it would much contribute to explain the phenomena of
northern lights. I have travelled much in the night, in all seasons of
the year, and over all kinds of soil, but never saw one of these Will
o'wisps.]

[_Shine round Calendula_. l. 191. See note on Tropaeolum in Vol. II.]

[_The radiant Worm_. l. 193. See additional notes, No. IX.]

[_The dread Gymnotus_. l. 202. The Gymnotus electricus is a native of
the river of Surinam in South America; those which were brought over to
England about eight years ago were about three or four feet long, and
gave an electric shock (as I experienced) by putting one finger on the
back near its head, and another of the opposite hand into the water near
its tail. In their native country they are said to exceed twenty feet in
length, and kill any man who approaches them in an hostile manner. It is
not only to escape its enemies that this surprizing power of the fish is
used, but also to take its prey; which it does by benumbing them and
then devouring them before they have time to recover, or by perfectly
killing them; for the quantity of the power seemed to be determined by
the will or anger of the animal; as it sometimes struck a fish twice
before it was sufficiently benumbed to be easily swallowed.

The organs productive of this wonderful accumulation of electric matter
have been accurately dissected and described by Mr. J. Hunter. Philos.
Trans. Vol. LXV. And are so divided by membranes as to compose a very
extensive surface, and are supplied with many pairs of nerves larger
than any other nerves of the body; but how so large a quantity is so
quickly accumulated as to produce such amazing effects in a fluid ill
adapted for the purpose is not yet satisfactorily explained. The Torpedo
possesses a similar power in a less degree, as was shewn by Mr. Walch,
and another fish lately described by Mr. Paterson. Philo. Trans. Vol.
LXXVI.

In the construction of the Leyden-Phial, (as it is called) which is
coated on both sides, it is known, that above one hundred times the
quantity of positive electricity can be condensed on every square inch
of the coating on one side, than could have been accumulated on the same
surface if there had been no opposite coating communicating with the
earth; because the negative electricity, or that part of it which caused
its expansion, is now drawn off through the glass. It is also well
known, that the thinner the glass is (which is thus coated on both sides
so as to make a Leyden-phial, or plate) the more electricity can be
condensed on one of its surfaces, till it becomes so thin as to break,
and thence discharge itself.

Now it is possible, that the quantity of electricity condensible on one
side of a coated phial may increase in some high ratio in respect to the
thinness of the glass, since the power of attraction is known to
decrease as the squares of the distances, to which this circumstance of
electricity seems to bear some analogy. Hence if an animal membrane, as
thin as the silk-worm spins its silk, could be so situated as to be
charged like the Leyden bottle, without bursting, (as such thin glass
would be liable to do,) it would be difficult to calculate the immense
quantity of electric fluid, which might be accumulated on its surface.
No land animals are yet discovered which possess this power, though the
air would have been a much better medium for producing its effects;
perhaps the size of the necessary apparatus would have been inconvenient
to land animals.]

[_In his shining claws_. l. 208. Alluding to an antique gem in the
collection of the Grand Duke of Florence. Spence.]

V. 1. "NYMPHS! Your soft smiles uncultur'd man subdued,
210 And charm'd the Savage from his native wood;
You, while amazed his hurrying Hords retire
From the fell havoc of devouring FIRE,
Taught, the first Art! with piny rods to raise
By quick attrition the domestic blaze,
215 Fan with soft breath, with kindling leaves provide,
And lift the dread Destroyer on his side.
So, with bright wreath of serpent-tresses crown'd,
Severe in beauty, young MEDUSA frown'd;
Erewhile subdued, round WISDOM'S Aegis roll'd
220 Hiss'd the dread snakes, and flam'd in burnish'd gold;
Flash'd on her brandish'd arm the immortal shield,
And Terror lighten'd o'er the dazzled field.

[_Of devouring fire_. l. 212. The first and most important discovery of
mankind seems to have been that of fire. For many ages it is probable
fire was esteemed a dangerous enemy, known only by its dreadful
devastations; and that many lives must have been lost, and many
dangerous burns and wounds must have afflicted those who first dared to
subject it to the uses of life. It is said that the tall monkies of
Borneo and Sumatra lie down with pleasure round any accidental fire in
their woods; and are arrived to that degree of reason, that knowledge of
causation, that they thrust into the remaining fire the half-burnt ends
of the branches to prevent its going out. One of the nobles of the
cultivated people of Otaheita, when Captain Cook treated them with tea,
catched the boiling water in his hand from the cock of the tea-urn, and
bellowed with pain, not conceiving that water could become hot, like red
fire.

Tools of steel constitute another important discovery in consequence of
fire; and contributed perhaps principally to give the European nations
so great superiority over the American world. By these two agents, fire
and tools of steel, mankind became able to cope with the vegetable
kingdom, and conquer provinces of forests, which in uncultivated
countries almost exclude the growth of other vegetables, and of those
animals which are necessary to our existence. Add to this, that the
quantity of our food is also increased by the use of fire, for some
vegetables become salutary food by means of the heat used in cookery,
which are naturally either noxious or difficult of digestion; as
potatoes, kidney-beans, onions, cabbages. The cassava when made into
bread, is perhaps rendered mild by the heat it undergoes, more than by
expressing its superfluous juice. The roots of white bryony and of arum,
I am informed lose much of their acrimony by boiling.]

[_Young Medusa frowned_. l. 218. The Egyptian Medusa is represented on
antient gems with wings on her head, snaky hair, and a beautiful
countenance, which appears intensely thinking; and was supposed to
represent divine wisdom. The Grecian Medusa, on Minerva's shield, as
appears on other gems, has a countenance distorted with rage or pain,
and is supposed to represent divine vengeance. This Medusa was one of
the Gorgons, at first very beautiful and terrible to her enemies;
Minerva turned her hair into snakes, and Perseus having cut off her head
fixed it on the shield of that goddess; the sight of which then
petrified the beholders. Dannet Dict.]

2. NYMPHS! YOU disjoin, unite, condense, expand,
And give new wonders to the Chemist's hand;
225 On tepid clouds of rising steam aspire,
Or fix in sulphur all it's solid fire;
With boundless spring elastic airs unfold,
Or fill the fine vacuities of gold;
With sudden flash vitrescent sparks reveal,
230 By fierce collision from the flint and steel;
Or mark with shining letter KUNKEL's name
In the pale Phosphor's self-consuming flame.
So the chaste heart of some enchanted Maid
Shines with insidious light, by Love betray'd;
235 Round her pale bosom plays the young Desire,
And slow she wastes by self-consuming fire.

[_Or fix in sulphur_. l. 226. The phenomena of chemical explosions
cannot be accounted for without the supposition, that some of the bodies
employed contain concentrated or solid heat combined with them, to which
the French Chemists have given the name of Calorique. When air is
expanded in the air-pump, or water evaporated into steam, they drink up
or absorb a great quantity of heat; from this analogy, when gunpowder is
exploded it ought to absorb much heat, that is, in popular language, it
ought to produce a great quantity of cold. When vital air is united with
phlogistic matter in respiration, which seems to be a slow combustion,
its volume is lessened; the carbonic acid, and perhaps phosphoric acid
are produced; and heat is given out; which according to the experiments
of Dr. Crawford would seem to be deposited from the vital air. But as
the vital air in nitrous acid is condensed from a light elastic gas to
that of a heavy fluid, it must possess less heat than before. And hence
a great part of the heat, which is given out in firing gunpowder, I
should suppose, must reside in the sulphur or charcoal.

Mr. Lavoisier has shewn, that vital air, or Oxygene, looses less of its
heat when it becomes one of the component parts of nitrous acid, than in
any other of its combinations; and is hence capable of giving out a
great quantity of heat in the explosion of gunpowder; but as there seems
to be great analogy between the matter of heat, or Calorique, and the
electric matter; and as the worst conductors of electricity are believed
to contain the greatest quantity of that fluid; there is reason to
suspect that the worst conductors of heat may contain the most of that
fluid; as sulphur, wax, silk, air, glass. See note on l. 174 of this
Canto.]

[_Vitrescent sparks_. l. 229. When flints are struck against other
flints they have the property of giving sparks of light; but it seems to
be an internal light, perhaps of electric origin, very different from
the ignited sparks which are struck from flint and steel. The sparks
produced by the collision of steel with flint appear to be globular
particles of iron, which have been fused, and imperfectly scorified or
vitrified. They are kindled by the heat produced by the collision; but
their vivid light, and their fusion and vitrification are the effects of
a combustion continued in these particles during their passage through
the air. This opinion is confirmed by an experiment of Mr. Hawksbee, who
found that these sparks could not be produced in the exhausted receiver.
See Keir's Chemical Dict. art. Iron, and art. Earth vitrifiable.]

[_The pale Phosphor_. l. 232. See additionable notes, No. X.]

3. "YOU taught mysterious BACON to explore
Metallic veins, and part the dross from ore;
With sylvan coal in whirling mills combine
240 The crystal'd nitre, and the sulphurous mine;
Through wiry nets the black diffusion strain,
And close an airy ocean in a grain.--
Pent in dark chambers of cylindric brass
Slumbers in grim repose the sooty mass;
245 Lit by the brilliant spark, from grain to grain
Runs the quick fire along the kindling train;
On the pain'd ear-drum bursts the sudden crash,
Starts the red flame, and Death pursues the flash.--
Fear's feeble hand directs the fiery darts,
250 And Strength and Courage yield to chemic arts;
Guilt with pale brow the mimic thunder owns,
And Tyrants tremble on their blood-stain'd thrones.

[_And close an airy ocean_. l. 242. Gunpowder is plainly described in
the works of Roger Bacon before the year 1267. He describes it in a
curious manner, mentioning the sulphur and nitre, but conceals the
charcoal in an anagram. The words are, sed tamen salis petrae _lure mope
can ubre_, et sulphuris; et sic facies tonitrum, et corruscationem, si
scias, artificium. The words lure mope can ubre are an anagram of
carbonum pulvere. Biograph. Britan. Vol. I. Bacon de Secretis Operibus,
Cap. XI. He adds, that he thinks by an artifice of this kind Gideon
defeated the Midianites with only three hundred men. Judges, Chap. VII.
Chamb. Dict. art. Gunpowder. As Bacon does not claim this as his own
invention, it is thought by many to have been of much more antient
discovery.

The permanently elastic fluid generated in the firing of gunpowder is
calculated by Mr. Robins to be about 244 if the bulk of the powder be 1.
And that the heat generated at the time of the explosion occasions the
rarefied air thus produced to occupy about 1000 times the space of the
gunpowder. This pressure may therefore be called equal to 1000
atmospheres or six tons upon a square inch. As the suddenness of this
explosion must contribute much to its power, it would seem that the
chamber of powder, to produce its greatest effect, should be lighted in
the centre of it; which I believe is not attended to in the manufacture
of muskets or pistols.

From the cheapness with which a very powerful gunpowder is likely soon
to be manufactured from aerated marine acid, or from a new method of
forming nitrous acid by means of mangonese or other calciform ores, it
may probably in time be applied to move machinery, and supersede the use
of steam.

There is a bitter invective in Don Quixot against the inventors of gun-
powder, as it levels the strong with the weak, the knight cased in steel
with the naked shepherd, those who have been trained to the sword, with
those who are totally unskilful in the use of it; and throws down all
the splendid distinctions of mankind. These very reasons ought to have
been urged to shew that the discovery of gunpowder has been of public
utility by weakening the tyranny of the few over the many.]

VI. NYMPHS! You erewhile on simmering cauldrons play'd,
And call'd delighted SAVERY to your aid;
255 Bade round the youth explosive STEAM aspire
In gathering clouds, and wing'd the wave with fire;
Bade with cold streams the quick expansion stop,
And sunk the immense of vapour to a drop.--
Press'd by the ponderous air the Piston falls
260 Resistless, sliding through it's iron walls;
Quick moves the balanced beam, of giant-birth,
Wields his large limbs, and nodding shakes the earth.

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