The Botanic Garden
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Erasmus Darwin >> The Botanic Garden
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An atmosphere of inflammable air above the common atmosphere principally
about the poles 123
Twilight fifty miles high. Wants further observations 126
Immediate cause of volcanos from steam and other vapours. They prevent
greater earthquakes 152
Conductors of heat. Cold on the tops of mountains 176
Phosphorescent light in the evening from all bodies 177
Phosphoric light from calcined shells. Bolognian stone. Experiments of
Beccari and Wilson 182
Ignis fatuus doubtful 189
Electric Eel. Its electric organs. Compared to the electric Leyden phial
202
Discovery of fire. Tools of steel. Forests subdued. Quantity of food
increased by cookery 212
Medusa originally an hieroglyphic of divine wisdom 218
Cause of explosions from combined heat. Heat given out from air in
respiration. Oxygene looses less heat when converted into nitrous acid
than in any other of its combinations 226
Sparks from the collision of flints are electric. From the collision of
flint and steel are from the combustion of the steel 229
Gunpowder described by Bacon. Its power. Should be lighted in the
centre. A new kind of it. Levels the weak and strong 242
Steam-engine invented by Savery. Improved by Newcomen. Perfected by Watt
and Boulton 254
Divine benevolence. The parts of nature not of equal excellence 278
Mr. Boulton's steam-engine for the purpose of coining would save many
lives from the executioner 281
Labours of Hercules of great antiquity. Pillars of Hercules. Surface of
the Mediteranean lower than the Atlantic. Abyla and Calpe. Flood of
Deucalion 297
Accumulation of electricity not from friction 335
Mr. Bennet's sensible electrometer 345
Halo of saints is pictorial language 358
We have a sense adapted to perceive heat but not electricity 365
Paralytic limbs move by electric influence 367
Death of Professor Richman by electricity 373
Lightning drawn from the clouds. How to be safe in thunder storms 383
Animal heat from air in respiration. Perpetual necessity of respiration.
Spirit of animation perpetually renewed 401
Cupid rises from the egg of night. Mrs. Cosway's painting of this
subject 413
Western-winds. Their origin. Warmer than south-winds. Produce a thaw
430
Water expands in freezing. Destroys succulent plants, not resinous ones.
Trees in valleys more liable to injury. Fig-trees bent to the ground in
winter 439
Buds and bulbs are the winter cradle of the plant. Defended from frost
and from insects. Tulip produces one flower-bulb and several leaf-bulbs,
and perishes. 460
Matter of heat is different from light. Vegetables blanched by exclusion
of light. Turn the upper surface of their leaves to the light. Water
decomposed as it escapes from their pores. Hence vegetables purify air
in the day time only. 462
Electricity forwards the growth of plants. Silk-worms electrised spin
sooner. Water decomposed in vegetables, and by electricity 463
Sympathetic inks which appear by heat, and disappear in the cold. Made
from cobalt 487
Star in Cassiope's chair 515
Ice-islands 100 fathoms deep. Sea-ice more difficult of solution. Ice
evaporates producing great cold. Ice-islands increase. Should be
navigated into southern climates. Some ice-islands have floated
southwards 60 miles long. Steam attending them in warm climates 529
Monsoon cools the sands of Abyssinia 547
Ascending vapours are electrised plus, as appears from an experiment of
Mr. Bennet. Electricity supports vapour in clouds. Thunder showers from
combination of inflammable and vital airs 553
CANTO II.
Solar volcanos analogous to terrestrial and lunar ones. Spots of the sun
are excavations 14
Spherical form of the earth. Ocean from condensed vapour. Character of
Mr. Whitehurst 17
Granite the oldest part of the earth. Then limestone. And lastly, clay,
iron, coal, sandstone. Three great concentric divisions of the globe
35
Formation of primeval islands before the production of the moon.
Paradise. The Golden Age. Rain-bow. Water of the sea originally fresh
36
Venus rising from the sea an hieroglyphic emblem of the production of
the earth beneath the ocean 47
First great volcanos in the central parts of the earth. From steam,
inflammable gas, and vital air. Present volcanos like mole-hills 68
Moon has little or no atmosphere. Its ocean is frozen. Is not yet
inhabited, but may be in time 82
Earth's axis changed by the ascent of the moon. Its diurnal motion
retarded. One great tide 84
Limestone produced from shells. Spars with double refractions. Marble.
Chalk 93
Antient statues of Hercules. Antinous. Apollo. Venus. Designs of
Roubiliac. Monument of General Wade. Statues of Mrs. Damer 101
Morasses rest on limestone. Of immense extent 116
Salts from animal and vegetable bodies decompose each other, except
marine salt. Salt mines in Poland. Timber does not decay in them. Rock-
salt produced by evaporation from sea-water. Fossil shells in salt
mines. Salt in hollow pyramids. In cubes. Sea-water contains about one-
thirtieth of salt 119
Nitre, native in Bengal and Italy. Nitrous gas combined with vital air
produces red clouds, and the two airs occupy less space than one of them
before, and give out heat. Oxygene and azote produce nitrous acid 143
Iron from decomposed vegetables. Chalybeat springs. Fern-leaves in
nodules of iron. Concentric spheres of iron nodules owing to polarity,
like iron-filings arranged by a magnet. Great strata of the earth owing
to their polarity 183
Hardness of steel for tools. Gave superiority to the European nations.
Welding of steel. Its magnetism. Uses of gold 192
Artificial magnets improved by Savery and Dr. Knight, perfected by Mr.
Michel. How produced. Polarity owing to the earth's rotatory motion. The
electric fluid, and the matter of heat, and magnetism gravitate on each
other. Magnetism being the lightest is found nearest the axis of the
motion. Electricity produces northern lights by its centrifugal motion
193
Acids from vegetable recrements. Flint has its acid from the new world.
Its base in part from the old world, and in part from the new. Precious
stones 215
Diamond. Its great refraction of light. Its volatibility by heat. If an
inflammable body. 228
Fires of the new world from fermentation. Whence sulphur and bitumen by
sublimation, the clay, coal, and flint remaining 275
Colours not distinguishable in the enamel-kiln, till a bit of dry wood
is introduced 283
Etrurian pottery prior to the foundations of Rome. Excelled in fine
forms, and in a non-vitreous encaustic painting, which was lost till
restored by Mr. Wedgwood. Still influences the taste of the inhabitants
291
Mr. Wedgwood's cameo of a slave in chains, and of Hope 315
Basso-relievos of two or more colours not made by the antients. Invented
by Mr. Wedgwood 342
Petroleum and naptha have been sublimed. Whence jet and amber. They
absorb air. Attract straws when rubbed. Electricity from electron the
greek name for amber 353
Clefts in granite rocks in which metals are found. Iron and manganese
found in all vegetables. Manganese in limestone. Warm springs from steam
rising up the clefts of granite and limestone. Ponderous earth in
limestone clefts and in granite. Copper, lead, iron, from descending
materials. High mountains of granite contain no ores near their summits.
Transmutation of metals. Of lead into calamy. Into silver 398
Armies of Cambytes destroyed by famine, and by sand-storms 435
Whirling turrets of sand described and explained 478
Granite shews iron as it decomposes. Marble decomposes. Immense quantity
of charcoal exists in limestone. Volcanic slags decompose, and become
clay 523
Millstones raised by wooden pegs 524
Hannibal made a passage by fire over the Alps 534
Passed tense of many words twofold, as driven or drove, spoken or spoke.
A poetic licence 609
CANTO III.
Clouds consist of aqueous spheres, which do not easily unite, like
globules of quicksilver, as may be seen in riding through water. Owing
to electricity. Snow. Hailstones rounded by attrition and dissolution of
their angles. Not from frozen drops of water 15
Dew on points and edges of grass, or hangs over cabbage-leaves, needle
floats on water 18
Mists over rivers and on mountains. Halo round the moon. Shadow of a
church-steeple upon a mist. Dry mist, or want of transparency of the
air, a sign of fair-weather 20
Tides on both sides of the earth. Moon's tides should be much greater
than the earth's tides. The ocean of the moon is frozen 61
Spiral form of shells saves calcareous matter. Serves them as an organ
of hearing. Calcareous matter produced from inflamed membranes. Colours
of shells, labradore-stone from mother-pearl. Fossil shells not now
found recent 66
Sea-insects like flowers. Actinia 82
Production of pearls, not a disease of the fish. Crab's eyes. Reservoirs
of pearly matter 84
Rocks of coral in the south-sea. Coralloid limestone at Linsel, and
Coalbrook Dale 90
Rocks thrown from mountains, ice from glaciers, and portions of earth,
or morasses, removed by columns of water. Earth-motion in Shropshire.
Water of wells rising above the level of the ground. St. Alkmond's well
near Derby might be raised many yards, so as to serve the town. Well at
Sheerness, and at Hartford in Connecticut 116
Moonsoons attended with rain Overflowing of the Nile. Vortex of
ascending air. Rising of the Dogstar announces the floods of the Nile.
Anubis hung out upon their temples 129
Situations exempt from rain. At the Line in Lower Egypt. On the coast of
Peru 138
Giesar, a boiling fountain in Iceland. Water with great degrees of heat
dissolves siliceous matter. Earthquake from steam 150
Warm springs not from decomposed pyrites. From steam rising up fissures
from great depths 166
Buxton bath possesses 82 degrees of heat. Is improperly called a warm
bath. A chill at immersion, and then a sensation of warmth, like the eye
in an obscure room owing to increased sensibility of the skin 184
Water compounded of pure air and inflammable air with as much matter of
heat as preserves it fluid. Perpetually decomposed by vegetables in the
sun's light, and recomposed in the atmosphere 204
Mythological interpretation of Jupiter and Juno designed as an emblem of
the composition of water from two airs 260
Death of Mrs. French 308
Tomb of Mr. Brindley 341
Invention of the pump. The piston lifts the atmosphere above it. The
surrounding atmosphere presses up the water into the vacuum. Manner in
which a child sucks 366
Air-cell in engines for extinguishing fire. Water dispersed by the
explosion of Gunpowder. Houses preserved from fire by earth on the
floors, by a second ceiling of iron-plates or coarse mortar. Wood
impregnated with alabaster or flint 406
Muscular actions and sensations of plants 460
River Achelous. Horn of Plenty 495
Flooding lands defends them from vernal frosts. Some springs deposit
calcareous earth. Some contain azotic gas, which contributes to produce
nitre. Snow water less serviceable 540
CANTO IV.
Cacalia produces much honey, that a part may be taken by insects without
injury 2
Analysis of common air. Source of azote. Of Oxygene. Water decomposed by
vegetable pores and the sun's light. Blood gives out phlogiston and
receives vital air. Acquires heat and the vivifying principle 34
Cupid and Psyche 48
Simoom, a pestilential wind. Described. Owing to volcanic electricity.
Not a whirlwind 65
Contagion either animal or vegetable 82
Thyrsis escapes the Plague 91
Barometer and air-pump, Dew on exhausting the receiver though the
hygrometer points to dryness. Rare air will dissolve or acquire more
heat, and more moisture, and more electricity 128
Sound propagated best by dense bodies, as wood, and water, and earth.
Fish in spiral shells all ear 164
Discoveries of Dr. Priestley. Green vegetable matter. Pure air contained
in the calces of metals, as minium, manganese, calamy, ochre 166
Fable of Proserpine an antient chemical emblem 178
Diving balloons supplied with pure air from minium. Account of one by
Mr. Boyle 195
Mr. Day. Mr. Spalding 217
Captain Pierce and his daughters 219
Pestilential winds of volcanic origin. Jordan flows through a country of
volcanos 294
Change of wind owing to small causes. If the wind could be governed, the
products of the earth would be doubled, and its number of inhabitants
increased 308
Mr. Kirwan's treatise on temperature of climates 342
Seeds of plants. Spawn of fish. Nutriment lodged in seeds. Their
preservation in their seed-vessels 355
Fixed stars approach each other 369
Fable of the Phoenix 377
Plants visible within bulbs, and buds, and seeds 383
Great Egg of Night 406
Seeds shoot into the ground. Pith. Seed-lobes. Starch converted into
sugar. Like animal chyle 411
Light occasions the actions of vegetable muscles. Keeps them awake
422
Vegetable love in Parnassia, Nigella. Vegetable adultery in Collinsonia
456
Strong vegetable shoots and roots bound with wire, in part debarked,
whence leaf-buds converted into flower-buds. Theory of this curious fact
463
Branches bent to the horizon bear more fruit 466
Engrafting of a spotted passion-flower produced spots upon the stock.
Apple soft on one side and hard on the other 483
Cyprepedium assumes the form of a large spider to affright the humming-
bird. Fly-ophris. Willow-wren sucks the honey of the crown-imperial
505
Diseases of plants four kinds. Honey-dew 511
Ergot a disease of rye 513
Glass unannealed. Its cracks owing to elasticity. One kind of lead-ore
cracks into pieces. Prince Rupert's drops. Elastic balls 519
Sleep of plants. Their irritability, sensibility, and voluntary motions
538
ADDITIONAL NOTES.
NOTE I.--METEORS.
_Etherial Forms! you chase the shooting stars,
Or yoke the vollied lightnings to your cars._
CANTO I. l. 115.
There seem to be three concentric strata of our incumbent atmosphere; in
which, or between them, are produced four kinds of meteors; lightning,
shooting stars, fire-balls, and northern lights. First, the lower region
of air, or that which is dense enough to resist by the adhesion of its
particles the descent of condensed vapour, or clouds, which may extend
from one to three or four miles high. In this region the common
lightning is produced from the accumulation or defect of electric matter
in those floating fields of vapour either in respect to each other, or
in respect to the earth beneath them, or the dissolved vapour above
them, which is constantly varying both with the change of the form of
the clouds, which thus evolve a greater or less surface; and also with
their ever-changing degree of condensation. As the lightning is thus
produced in dense air, it proceeds but a short course on account of the
greater resistance which it encounters, is attended with a loud
explosion, and appears with a red light.
2. The second region of the atmosphere I suppose to be that which has
too little tenacity to support condensed vapour or clouds; but which yet
contains invisible vapour, or water in aerial solution. This aerial
solution of water differs from that dissolved in the matter of heat, as
it is supported by its adhesion to the particles of air, and is not
precipitated by cold. In this stratum it seems probable that the meteors
called shooting stars are produced; and that they consist of electric
sparks, or lightning, passing from one region to another of these
invisible fields of aero-aqueous solution. The height of these shooting
stars has not yet been ascertained by sufficient observation; Dr.
Blagden thinks their situation is lower down in the atmosphere than that
of fireballs, which he conjectures from their swift apparent motion, and
ascribes their smallness to the more minute division of the electric
matter of which they are supposed to consist, owing to the greater
resistance of the denser medium through which they pass, than that in
which the fire-balls exist. Mr. Brydone observed that the shooting stars
appeared to him to be as high in the atmosphere, when he was near the
summit of mount Etna, as they do when observed from the plain. Phil.
Tran. Vol. LXIII.
As the stratum of air, in which shooting stars are supposed to exist is
much rarer than that in which lightning resides, and yet much denser
than that in which fire-balls are produced, they will be attracted at a
greater distance than the former, and at a less than the latter. From
this rarity of the air so small a sound will be produced by their
explosion, as not to reach the lower parts of the atmosphere; their
quantity of light from their greater distance being small, is never seen
through dense air at all, and thence does not appear red, like lightning
or fire balls. There are no apparent clouds to emit or to attract them,
because the constituent parts of these aero-aqueous regions may possess
an abundance or deficiency of electric matter and yet be in perfect
reciprocal solution. And lastly their apparent train of light is
probably owing only to a continuance of their impression on the eye; as
when a fire-stick is whirled in the dark it gives the appearance of a
compleat circle of fire: for these white trains of shooting stars
quickly vanish, and do not seem to set any thing on fire in their
passage, as seems to happen in the transit of fire-balls.
3. The second region or stratum of air terminates I suppose where the
twilight ceases to be refracted, that is, where the air is 3000 times
rarer than at the surface of the earth; and where it seems probable that
the common air ends, and is surrounded by an atmosphere of inflammable
gas tenfold rarer than itself. In this region I believe fire-balls
sometimes to pass, and at other times the northern lights to exist. One
of these fire-balls or draco volans, was observed by Dr. Pringle and
many others on Nov. 26, 1758, which was afterwards estimated to have
been a mile and a half in circumference, to have been about one hundred
miles high, and to have moved towards the north with a velocity of near
thirty miles in a second of time. This meteor had a real tail many miles
long, which threw off sparks in its course, and the whole exploded with
a sound like distant thunder. Philos. Trans. Vol. LI.
Dr. Blagden has related the history of another large meteor, or fire-
ball, which was seen the 18th of August, 1783, with many ingenious
observations and conjectures. This was estimated to be between 60 and 70
miles high, and to travel 1000 miles at the rate of about twenty miles
in a second. This fire-ball had likewise a real train of light left
behind it in its passage, which varied in colour; and in some part of
its course gave off sparks or explosions where it had been brightest;
and a dusky red streak remained visible perhaps a minute. Philos. Trans.
Vol. LXXIV.
These fire-balls differ from lightning, and from shooting stars in many
remarkable circumstances; as their very great bulk, being a mile and a
half in diameter; their travelling 1000 miles nearly horizontally; their
throwing off sparks in their passage; and changing colours from bright
blue to dusky red; and leaving a train of fire behind them, continuing
about a minute. They differ from the northern lights in not being
diffused, but passing from one point of the heavens to another in a
defined line; and this in a region above the crepuscular atmosphere,
where the air is 3000 tines rarer than at the surface of the earth.
There has not yet been even a conjecture which can account for these
appearances!--One I shall therefore hazard; which, if it does not
inform, may amuse the reader.
In the note on l. 123, it was shewn that there is probably a supernatant
stratum of inflammable gas or hydrogene, over the common atmosphere; and
whose density at the surface where they meet, must be at least ten times
less than that upon which it swims; like chemical ether floating upon
water, and perhaps without any real contact. 1. In this region, where
the aerial atmosphere terminates and the inflammable one begins, the
quantity of tenacity or resistance must be almost inconceivable; in
which a ball of electricity might pass 1000 miles with greater ease than
through a thousandth part of an inch of glass. 2. Such a ball of
electricity passing between inflammable and common air would set fire to
them in a line as it patted along; which would differ in colour
according to the greater proportionate commixture of the two airs; and
from the same cause there might occur greater degrees of inflammation,
or branches of fire, in some parts of its course.
As these fire-balls travel in a defined line, it is pretty evident from
the known laws of electricity, that they must be attracted; and as they
are a mile or more in diameter, they must be emitted from a large
surface of electric matter; because large nobs give larger sparks, less
diffused, and more brightly luminous, than less ones or points, and
resist more forceably the emission of the electric matter. What is there
in nature can attract them at so great a distance as 1000 miles, and so
forceably as to detach an electric spark of a mile diameter? Can
volcanos at the time of their eruptions have this effect, as they are
generally attended with lightning? Future observations must discover
these secret operations of nature! As a stream of common air is carried
along with the passage of electric aura from one body to another; it is
easy to conceive, that the common air and the inflammable air between
which the fire-ball is supposed to pass, will be partially intermixed by
being thus agitated, and so far as it becomes intermixed it will take
fire, and produce the linear flame and branching sparks above described.
In this circumstance of their being attracted, and thence passing in a
defined line, the fire-balls seem to differ from the coruscations of the
aurora borealis, or northern lights, which probably take place in the
same region of the atmosphere; where the common air exists in extreme
tenuity, and is covered by a still rarer sphere of inflammable gas, ten
times lighter than itself.
As the electric streams, which constitute these northern lights, seem to
be repelled or radiated from an accumulation of that fluid in the north,
and not attracted like the fireballs; this accounts for the diffusion of
their light, as well as the silence of their passage; while their
variety of colours, and the permanency of them, and even the breadth of
them in different places, may depend on their setting on fire the
mixture of inflammable and common air through which they pass; as seems
to happen in the transit of the fire-balls.
It was observed by Dr. Priestley that the electric shock taken through
inflammable air was red, in common air it is blueish; to these
circumstances perhaps some of the colours of the northern lights may
bear analogy; though the density of the medium through which light is
seen must principally vary its colour, as is well explained by Mr.
Morgan. Phil. Trans. Vol. LXXV. Hence lightning is red when seen through
a dark cloud, or near the horizon; because the more refrangible rays
cannot permeate so dense a medium. But the shooting stars consist of
white light, as they are generally seen on clear nights, and nearly
vertical: in other situations their light is probably too faint to come
to us. But as in some remarkable appearances of the northern lights, as
in March, 1716, all the prismatic colours were seen quickly to succeed
each other, these appear to have been owing to real combustion; as the
density of the interposed medium could not be supposed to change so
frequently; and therefore these colours must have been owing to
different degrees of heat according to Mr. Morgan's theory of
combustion. In Smith's Optics, p. 69. the prismatic colours, and optical
deceptions of the northern lights are described by Mr. Cotes.
The Torricellian vacuum, if perfectly free from air, is said by Mr.
Morgan and others to be a perfect non-conductor. This circumstance
therefore would preclude the electric streams from rising above the
atmosphere. But as Mr. Morgan did not try to pass an electric shock
through a vacuum, and as air, or something containing air, surrounding
the transit of electricity may be necessary to the production of light,
the conclusion may perhaps still be dubious. If however the streams of
the northern lights were supposed to rise above our atmosphere, they
would only be visible at each extremity of their course; where they
emerge from, or are again immerged into the atmosphere; but not in their
journey through the vacuum; for the absence of electric light in a
vacuum is sufficiently proved by the common experiment of shaking a
barometer in the dark; the electricity, produced by the friction of the
mercury in the glass at its top, is luminous if the barometer has a
little air in it; but there is no light if the vacuum be complete.
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