NOTE 1, p. 3.

The Horologe of Flora.

"Thus in each flower and simple bell,
That in our path betrodden lie,
Are sweet remembrancers who tell

How fast the winged moments fly." THE HOROLOGE OF FLORA is alluded to by Pliny with his usual felicity of thought and expression:-"Dedi tibi herbas horarum indices; et ut ne sole quidem oculos tuos a terra avoces, heliotropium ac lupinum circumaguntur cum illo. Cur etiam altius spectas, ipsumque cœlum scrutaris? Habes ante pedes tuos ecce Vergilias."-Hist. Nat., lib. xviii. c. 27,

Linnæus enumerates forty-six flowers which possess this kind of sensibility. The following are a few of them, with their respective hours of rising and setting, as the Swedish naturalist terms them. He divides them into

1st. Meteoric flowers, which less accurately observe the hour of unfolding, but are expanded sooner or later, according to the cloudiness, moisture, or pressure of the atmosphere.

2d. Tropical flowers, which open in the morning, and close before evening every day; but the hour of the expanding becomes earlier or later, as the length of the day increases or decreases.

3d. Equinoctial flowers, which serve for the construction of Flora's dial, since they open at a certain and exact hour of the day, and for the most part close at another determinate hour: for instance, the Leontodon taraxacum, dandelion, opens at 5-6, closes at 8-9; Hieracium pilosella, mouse-ear hawkweed, opens at 8, closes at 2; Tragopogon pratense, yellow goat's-beard, opens at sun

rise, and shuts at noon with such regularity, that the husbandman who adopts it as the signal of dinner-time need not fear to have his pudding too much or too little boiled; Sonchus lævis, smooth sow-thistle, opens at 5, closes at 11-12; Lactuca sativa, cultivated lettuce, opens at 7, closes at 10; Tragopogon luteus, yellow goat's-beard, opens at 3-5, closes at 9-10; Lapsana, nipplewort, opens at 5-6, closes at 10-11; Nymphæa alba, white water-lily, opens at 7, closes at 5; Papaver nudicaule, naked popy, opens at 5, closes at 7; Hemerocallis fulva, tawny day-lily, opens at 5, closes at 7-8; Convolvulus, opens at 5-6; Malva, mallow, opens at 9-10, closes at 1; Arenaria purpurea, purple sandwort, opens at 9-10, closes at 2-3; Anagallis, pimpernel, opens at 7-8; Portulaca hortensis, garden purslain, opens at 9-10, closes at 11-12; Dianthus prolifer, proliferous pink, opens at 8, closes at 1; Cichoreum, succory, opens at 4-5; Hypocharis opens at 6-7, closes at 4-5; Crepis opens at 4-5, closes at 10-11; Picris opens at 4-5, closes at 12; Calendula Africana opens at 7, closes at 3-4, &c.

In like manner may be formed a calendar of Flora: thus, if we consider the time of putting forth leaves, the honeysuckle protrudes them in the month of January; the gooseberry, currant, and elder in the end of February, or beginning of April; the oak and ash in the beginning, or towards the middle, of May, &c.

Notwithstanding the injunction implied in the quotation of Pliny at the head of the present note, we shall venture to direct the gaze of our readers to the northern pole of the sky-"petere

auxilium celeste"-whenever the sun fails to cast its tell-tale shadow on the dial; for in that region may be seen old Time pointing his finger to the hour of the day, even though the sun be below the horizon! Is it not passing strange that there should have existed, ever since the creation of the solar system, a never-failing chronometer telegraphing time, by a process unsuspected by man, until the keen eye of Science detected its working, and enabled him to recognise and interpret its signals? We must here take for granted that the reader is already acquainted with the nature of polarized light, for the subject is far too large to be discussed, or even enunciated in the compass of a note.

Suffice

it to say that from the disposition of the polarized beams of reflected light, as they stream from the northern sky, we can accurately infer the position of the sun, and consequently the hour of the day. To determine this, Mr Wheatstone has invented an optical instrument termed the Polar Clock, by which the plane of polarization can be easily ascertained. To those acquainted with the theory of polarization it will be evident that, since the sun, in its apparent daily course, moves equably in a circle round the north pole, so must the planes of polarization change their position exactly as the hour-circles change. A description of this ingenious instrument is to be found in the Report of the 18th Meeting of the British Association held at Swansea in 1848. In this note we only profess to direct attention to the subject.

NOTE 2, p. 4.

Geological Theories-Fire and Water. The geologist of the present day can scarcely imagine the uncompromising and intolerant spirit with which the partisans of the Igneous and Aqueous theories of the earth carried on their controversy during the earlier part of the present century. Edinburgh, originally the cradle, became the arena of the combatants. The Wernerians, or "Neptunists," as they were called, affirmed that the earth was indebted for its present form and arrangement to the sole agency of water; and thus, as Shakspeare says, "made a sop of all this solid globe;" the Huttonians, or "Plutonists," on the contrary, although they admitted to a certain extent the operation of water, maintained the utter

impossibility of explaining the consolidation of the strata without the intervention of fire; every geologist felt bound to side with one or the other of these contending parties, for neutrality was held as disgraceful as though the law of Solon had been in active operation.

Fire and water, in philosophical systems, as well as in poetical fables, had ever maintained an unmitigated hostility, until Chemistry stepped in as umpire to adjust their claims and settle their differences. This science soon determined that there did not really exist that antagonism which was so universally believed, but that water contained an element of fire, and fire an element of water, thus realising the prodigy in Livy-" Unda dabit flammas, et dabit ignis aquas."

When water was thus violently assailed by the geologic Plutonist, and driven, as it were, by a flaming sword from the rocky strata, it sought shelter and refuge in their imbedded crystals, and became, in its turn, the assailant. To quote the words of one of the most inflexible and eloquent disciples of Werner, the late Dr Clarke of Cambridge, "the water in the crystals of my cabinet is more than sufficient to extinguish all the fires of the Plutonist." This Quixotic attack upon his adversaries reminds us of the amusing old Pagan fable. The Persian and Egyptian priests of the gods of fire and water agreed upon a duel between their principals. The aquatic champion was clad, for armour, in a jug bored with holes stopped with wax. Flame advanced with all the fervour of his element; Neptune received the onset with sang froid: Flame rushed on, the wax dissolved, an inundation burst forth, and Flame was subdued and extinguished.

Hence the origin of the deified Pitcher (Canopus) common on the coins of Egypt-it being a human head placed upon a kind of pitcher. But since these early days of geological speculation, the science has lost its wildness of romance, and fallen into the ranks of inductive philosophy; and even those apparently fortuitous elevations and depressions, which diversify the surface of the globe, promise submission to a dynamic law which will ultimately, no doubt, reduce the whole to order and system.

NOTE 3, p. 15. Göthe an early but intelligent "Destructive."

"From my earliest years I felt a love for the investigation of natural things. It is often regarded as an instinct of cruelty, that children like, at last, to break, tear, and devour objects with which for a long time they played, and which they have handled in various manners; and yet even in this way is manifested the curiosity, the desire of learning how such things hang together-how they look within. I re

member that, as a child, I pulled flowers to pieces to see how the leaves were inserted into the calyx; or even plucked birds to observe how the feathers were inserted into the wings.

"Children are not to be blamed for this, when even our naturalists believe they get their knowledge oftener by separation and division than by union and combination-more by killing than by making alive." - Autobiography of

Göthe.

NOTE 4, p. 23.

Weight of the Earth and the Planets. "Th' Eternal hung forth His golden scales, Wherein all things created first He weighed."

MILTON.

The startling fact announced in the text, that the astronomer is not only able to measure the Earth and Planets, but to ascertain the weight, or gravitating force of each, is due to the wonderful discovery of universal gravitation; which enables him to infer, from the revolution of the satellites round their primary planets, a measure of the force by which they are retained in their orbits, and, consequently, a measure of the quantity of gravitating matter, of which each planet consists.

The planets differ greatly in magnitude: for example, the diameter of the earth is 8000 miles; that of Jupiter, 88,000; of Saturn, 75,000; and since the volumes, or bulks of globes, are in the proportion of the cubes of their diameters, it follows that the bulk of Jupiter is 1300 times that of the earth, while that of Saturn is 857 times; but we are now only speaking of magnitude, let us next consider the question of density. With regard to Jupiter, we are at once assisted by comparing the velocity of the moon's revolution round the earth with that of one of Jupiter's satellites,

when we find that, bulk for bulk, the matter composing Jupiter is lighter than that of the earth in the ratio of 1 to 4; in fact, that it is only a little heavier than water. Venus and Mars would appear to be 5.5 times heavier than water, being nearly of the same density as that of the earth; whereas Mercury has the specific weight of gold. Uranus and Neptune would seem to have the density of water; while Saturn is lighter than water, and would float in it like a piece of pine wood; nor does the sun exceed that of water; and yet it by no means follows that these light bodies exist in a fluid form. Sir David Brewster observes, that there are many solid bodies, and even some minerals, as pumice, and even the metals of the alkalis, of less specific gravity than water. Now this, with other inquiries relating to magnitude, distance, heat, and light, variation of seasons, length of the year, and other physical conditions, have an important bearing upon a question which has lately excited considerable discussion-that of the PLURALITY OF WORLDS -involving speculations regarding the physical adaptation of the planets, as the abodes of intellectual life, or of inhabitants to be regarded as the equivalents of the human race: and first, as to the gravitating influence of such large bodies upon animals moving on their surfaces. Independent of the influence of density, magnitude will considerably diminish the weight of any body on the surface of a planet; thus it is apparent that the larger the globe, the farther removed must be any body on its surface from its centre, in the proportion of the square of the distance. Let us illustrate this proposition by an appeal to Jupiter: the volume of that planet has been stated at 1300 times that of the earth; but a body on its surface is eleven times farther removed from its centre, and would therefore be attracted with a less force, in the ratio of the square of eleven, i.e., of 121 to 1; the necessary consequence of which will be that a body on its surface must weigh cleven times more than upon the earth; but we have just said that the matter of Jupiter has a density scarcely exceeding that of water; and hence we have farther to reduce our estimate, and instead of being eleven times, a body on its surface would only be 24 heavier than on our earth; and, therefore, physically speaking, the excessive amount

of gravitation would not, as it has been
argued, so fatally militate against the
possibility of animal existence. Besides,
is not adaptation, the paramount law of
creation? and what evidence is there to
show that intelligence bears any rela-
tion to weight or measure? We need
not the poetical fancy of Milton to
people these globes with forms adapted
to the exigencies of their several abodes;
it is by no means essential that they
should be, like the denizens of earth,
"Ty'd or manacled with joint or limb,

Nor founded on the brittle strength of bones,
Like cumbrous flesh."

With this passing notice we commit our readers to the safe keeping of Sir David Brewster.*

NOTE 5, p. 27.

Gravity and Centrifugal Force. It may, perhaps, be asked how this decrease of weight could have been ascertained since, if the body under examination decreased in weight, the weight which was opposed to it in the opposite scale must also have diminished in the same proportion; for instance, that, if the lump of lead lost two pounds, the body which served to balance it must also have lost the same weight, and therefore that the different force of gravity could not be detected by such means. It is undoubtedly true that the experiment in question could not have been performed with an ordinary pair of scales; but by using a spiral spring it was easy to compare the force of the lead's gravity at the surface of the earth, and at four miles high, by the relative degree of compression which it sustained in those different situations.

With respect to the effect of the centrifugal force, as alluded to in the text. it may be here observed, that it has been found by calculation that, at the equator, the diminution of gravity occasioned by the centrifugal force arising from the rotation of the earth amounts to about the 289th part. But since this number is the square of seventeen, it follows that, if our globe turned more than seventeen times faster about her axis, or performed the diurnal revolution within the space of eighty-four minutes, the centrifugal force would predominate over the powers of gra

"More Worlds than One; the Creed of the Philosopher, and the Hope of the Christian," by Sir David Brewster, K.H., D.C.L., F.R.S., &c.

vitation, and all the fluid and loose matters would, near the equinoctial boundary, have been projected from the surface. On such a supposition the waters of the ocean must have been drained off, and an impassable zone of sterility interposed between the opposite hemispheres. By a similar calculation, combined with that decreasing force of gravity at great distances from the centre, it may be inferred that the altitude of our atmosphere could never exceed 26,000 miles. Beyond this limit, the equatorial portion of air would have been shot into indefinite space. If it were possible to fire off a cannon-ball with a velocity of five miles in a second, and the resistance of the air could be taken away, it would for ever wheel round the earth, instead of falling upon it; and supposing the velocity to reach the rate of seven miles in a second, the ball would fly off from the earth, and be never heard of more.

NOTE 6, p. 29. Velocity of Light.

"THE STARS AND THE EARTH." "How distant some of these nocturnal Suns! So distant, says the sage, 'twere not absurd To doubt if beams, set out at Nature's birth, Are yet arrived at this so foreign world."

Young's Night Thoughts, N. ix.

It is scarcely possible so to strain the imagination as to conceive the velocity with which light travels. "What mere assertion," asks Sir J. Herschel, "will make any man believe that in one second of time-in one beat of the pendulum of a clock-a ray of light travels over 192,000 miles, and would, therefore, perform the tour of the world in about the same time that it requires to wink with our eyelids, and in much less than a swift runner occupies in taking a single stride!"

Were a cannon-ball, shot directly towards the sun, to retain its full speed, it would be twenty years in reaching it, and yet light travels through this space, not less than a hundred million of miles, in seven or eight minutes. It is only by thus bringing velocity into comparison with time and space that the human mind can grapple with a subject that startles the imagination by the vastness of the conception it inspires, while it arouses our reasoning faculties to the consciousness of the momentous questions involved in its examination. From the moon, which is distant from us

240,000 miles, its light will occupy in its passage to the earth about a second and a quarter of our time; from Jupiter, 617,000,000 miles distant, fifty-two minutes; and from Uranus, 1,800,000,000 from us, not less than two hours: but if these numbers startle the reader, what will he say when, quitting the confines of the solar system, we penetrate the infinite wilderness of space, and tell him that from the nearest fixed star, that, for example, which is the brightest in the constellation, Centaury, its light will require three years to reach the earth; from Vega, of the Lyre, twelve years; and from a star in the twelfth magnitude, no less than 4000 years! during which period this subtle emanation, or "light wave," must have flowed through space, on its own account, unconnected with its original source;* and, therefore, by seeing these stars, we only receive information of their visible condition; not what it is at present, but what it was some thousand years ago, when they sent forth their light on its infinite journey; so that, for aught we know or can tell, stars may have been created coeval with man, and yet their light may not yet have reached us; and stars may have been extinguished for many thousand years, and may still continue visible to us by means of the light emitted before their extinction, and which may continue to shine for centuries to come! What a subject for the exercise of the imagination !t

The first question, however, which very naturally suggests itself, is as to the nature of that force or impulse which we call light-is it matter sui generis?— or is it a transcendental condition of matter? Now two theories have been advanced for its explanation-the one known as the Newtonian, or that of emission, as it is called; the other, the undulatory theory. The former regards light as consisting of myriads of material particles, emitted by luminous bodies; the latter maintains that there

The author of "The Stars and the Earth" has fallen into an obvious fallacy when he states that "the moon rises above the horizon a second and a quarter before she becomes visible to us." It is the stream, not the source that enlightens us, and that has been uninterruptedly flowing, and falls upon the earth the moment it turns towards it.

The ancient philosophers would appear to have entertained a curious estimate as to the distance of the heavenly bodies. We find it stated in the "Theogony" of Hesiod that, such is the height of the heavens, a smith's anvil would be nine days in falling thence to the earth.

is no inactive void in creation, but that space is filled up by an "ether," penetrable by attractive forces, by which the universe is held together, and that the waves of this ether form light. This latter theory now prevails; since it has been found that, during the progress of optical discoveries, the former is wholly inadequate to meet their requirements, viz., the great class of phenomena of diffraction and polarization; but we must here again refer the reader to our Mentor, Sir David Brewster.*

The astronomer, placed on our puny globe, looks up at the stars, watches their motions, speculates upon their distances, foreshadows their destinics, and is lost in wonder. With the indulgence of the reader, as the pastime of an hour, or as "Philosophy in Sport," if it so please him to regard it, we will reverse the telescope and the prospect; and instead of gazing upon these gems of the heavens, like mortals from the earth, let us avail ourselves of the imaginary wings of the poet, "soar the blue profound, and look back upon all the stars." If it be admitted that some hundred years may be required to convey the light of a star to the earth, it is obvious that the same period must be relatively occupied by the transit of the earth's light to any star on which fancy might place us. This converse proposition has been adopted, and very ingeniously worked out by an anonymous author, in a short essay, entitled, " The Stars and the Earth," and we are anxious to bring it to the notice of the reader, as one of those bright bubbles that frequently rise up, during the effervescence of an ingenious mind, and which, like those of the well, may indicate the presence of truth at its bottom. The author calls upon us to admit certain postulates, viz.,-That force is never lost-that the powers of vision are illimitable-and that the word possible is to denote whatever does not contradict the laws of thought. If, then, we can imagine a being, with the same powers as those possessed by man, but on an enlarged scale, not differing in kind, but in degree, an earthly deed or occurrence, even after thousands of years, might, from a star of appropriate distance, that is to say, from a point at which the light and the reflec

"A Treatise on Optics," &c.

"The Stars and the Earth; or, Thoughts upon Space, Time, and Eternity." -Bailliere, Regent Street, and New York. Price One Shilling.