those forces which tend to turn the body in one direction be equal to the sum of the moments of those which tend to turn it in the opposite direction, these forces will produce equilibrium."*

As it may be interesting, and cannot fail to be instructive to our readers, to be made aware of the effects which would be produced by "any variation in the mean temperature" of revolving bodies, even on one of such stable equilibrium as the earth we tread on, we give the following from the pen of Mrs. Somerville, to which we have been already so deeply indebted for information on kindred subjects:

"But although these circumstances," she observes-when treating on the equality of the length of the day, and alluding to the ineffectual action on the diurnal rotation of rivers, trade winds, sun and moon, and of the eruption of volcanoes-"be insufficient, a variation in the mean temperature would certainly occasion a corresponding change in the velocity of rotation. In the science of dynamics, it is a principle in the system of bodies, or of particles revolving about a fixed centre, that the momentum, or sum of the products of the mass of each into its angular velocity and distance from the centre, is a constant quantity, if the system be not deranged by a foreign Now, since the number of the particles in the system is the same, whatever its temperature may be, when their distances from the centre are diminished, their angular velocity must be increased, in order that the preceding quantity may still remain constant. It follows, then, that as the primitive momentum of rotation with which the earth was projected into space must necessarily remain the same, the smallest decrease in heat, by contracting the terrestrial spheroid, would accelerate its rotation, and consequently diminish the length of the day."+

cause.

Now, it must be obvious to every one, after perusing what we have just stated, that as "the external light and heat which we receive comes from the sun," and is equally imparted to us, whatever be the position we occupy in space with relation to that luminary, those rays must be disseminated from it in all directions whether they emanate from the body itself, or from a luminiferous atmosphere which surrounds it. But then we have just learnt "that equal forces acting in opposite di

Cab. Cyc. vol. v. pp. 135, 136.

+ Connexion of the Sciences, p. 82.

rections, with a tendency to cause rotation, so far from producing that motion, neutralize each other's influence, and produce equilibrium." And, as in the case of the sun, without entering on the question of the influence exercised by rays of light on the body whence they emanate, the same light proceeds from its equatorial region in every direction, we are authorised to consider these rays to be equal forces acting in all these directions; and applying the mechanical law above cited to this assumption, to draw the undeniable conclusion, that the light as it is Now constituted cannot, and consequently, never could have caused the solid body of the sun to revolve around its axis. But, on the other hand, having been made aware, that the introduction of the primary material light into the universe occasioned the rotation of all bodies of our system around their respective axes, in which motion the central orb participates, the application of this truth to the conclusion we came to above, obliges us to consider, that although it was the light which caused the solid nucleus of the sun to rotate around its axis, it could not have been the light as now situated or as now constituted.

In fact, we consider the light of the first three days of the Mosaic week, that is, the primary light, to have been entirely different in its effects from that which was afterwards received

from the sun. We look upon it, that these bore a somewhat similar relation to each other, to that which now subsists between the invisible electro-magnetic streams, capable of being made, in the hands of a skilful operator, to produce such wonders in decomposition and composition, and the brilliant radiance which bursts forth from the same currents, when the wires by which they are conducted are charcoal tipped, and made to collapse upon each other. They now illumine and dazzle by their visible splendour; they powerfully affect the eye, but they no longer produce, hiddenly, those almost miraculous changes on other bodies which they did before, when passing along silently and unseen by means of their conductors. And so with the primary light, during the first three days of its existence, ere yet there was an atmosphere, its conductor, and before the sea and the land were separated from each other, it was wholly invisible, and wonder working.

And all this was in perfect accordance with eternal wisdom, for we firmly believe, that up to that period there was not a material eye, within the whole scope of the universe, which could either have been benefitted by, or have beheld it.

This forms the first of a continued series of proofs which we intend to bring forward in order to demonstrate, that the primary light did not reside in or around the sun during the first three days of the Mosaic week; but that on the fourth day, when God saw fit, he set the light in the firmament of heaven to give light upon the earth.

The next proof to be adduced is somewhat similar to the preceding, namely that had the light, from the first, been situated in its present centre, it could not have caused the earth to revolve around its axis. To substantiate this, let us consider it to be established, that our planet has rotatory motion; that it was impressed upon it by the expansive principle of the primary light; and that the sun's rays, proceeding in straight lines, strike the earth perpendicular to its surface, and consequently to its axis; and, then, let us become acquainted with what is contained in part of the eightieth Theorem"That if the force applied to a body be directed upon the axis, and at right angles to it, no rotatory motion will be produced.” And again, "If a sphere at rest in space receive an impulse passing through its centre of gravity, all its parts will move with an equal velocity in a STRAIGHT LINE."

Combining these truths with what has been admitted above, the following self-obvious conclusion must be the result:

That as the rays of sun-light (supposed, for a moment, to have been the impelling power) affect the earth in lines perpendicular to its centre of gravity, they could not, according to the mechanical axiom just cited, have caused the earth to revolve around its axis, so long as they impinged upon it in that direction. But as it has been admitted, that the earth does revolve, and that the introduction of the primary light into our system, and its division from the darkness, were the immediate secondary causes thereof, we are therefore necessitated, as in the preceding case, to look to some other relative position of the primary light with respect to the earth, and some other state of it as the cause of the rotation of this latter

body. It was not the light as at present constituted, but it was the light; therefore it must have been the light from some other centre, and consequently in some other condition.

Another corroborating proof can be drawn from nearly the same source; we allude to what is termed the obliquity of the ecliptic; the plane of the latter, or apparent path of the sun, being at present intersected by that of the equator at an angle of 23° 28'. Now, it has been considered by astronomers, that the longer axis of the elliptic orbit of the earth around the sun, coincided with the autumnal equinox about the period of the formation of the light; and it being admitted, that the light proceeds in straight lines from its centre, had it then flowed from the sun, it must have proceeded in lines parallel to the plane of the ecliptic; and, consequently, would have come into contact with the earth in such a direction as would have caused it (if it could have produced rotation at all under such circumstances) to have revolved with its axis perpendicular to that plane, or to the ecliptic, and not as it actually does, in lines perpendicular to the plane of the equator, which at present is 23° 28′, distant from the other, and formerly was somewhat more oblique; because this would be to admit the absurd conclusion, that the light could have acted in planes where it did not exist; or, what is the same thing, out of the plane where it was supposed to have been, if we imagine it to have been centered at that time around the sun. But as we have admitted, upon sufficient proof, that the primary light was actually the propelling power, whilst astronomy announces that the obliquity of the plane of the equator to that of the ecliptic, at the period we allude to, was nearly 24°, we are compelled, as in the preceding cases, to look to some other relative positions of the light with respect to the earth, and also to some other state of it for the explanation of the phenomenon in question; while the elaborate proofs and investigations we have gone through, domonstrate to a certainty, that as far as regards the DIRECTION OF THE IMPELLING POWER, the primary light which caused the earth to revolve, did not come from the solar centre of our system.

SECTION IX.

CONCENTRATION OF THE LIGHT AROUND THE SUN; AND THE COMPLETION OF THE WORK OF CREATION.

CHAPTER XXXVII.

Continuation of the argument commenced in the foregoing chapter. The nonconcentration of the Light, during the first three days of the Mosaic week, deduced from the measured quantity of light and heat received at present, from the sun. Astronomical evidences. Confirmatory conclusion come to from these facts. The same deduction drawn from the circumstance, that the act of illuminating the Sun caused it to become the teller of the Earth's signs, seasons, days, and years. Contemplation of the magnitude of the achievement whereby the expansive principle was permanently fixed in the centre of our system. Corroborative conclusion from the peculiar direction in which the primary light acted, in order to occasion the rotation of the Earth; and presumptive evidence of its being akin to electromagnetism.

HAVING been thus made aware, by arguments deduced in the preceding chapter, from the direction in which the light now flows to the earth, that it could not have caused it to rotate had it, when first formed, been concentrated around the sun; we intend in the present division, to pursue a distinct line of evidence in favour of the same argument; and to draw all our evidences from the quantity of light at present imparted daily by the sun to the earth. With this design we require to be made acquainted with the truths contained in the second Theorem before we can estimate their influence on what has been said, or on what we may have to advance. The proposition alluded to states, "That the earth is a non-luminous body, receiving its external light and heat from the sun. And that the heat received is a fixed quantity, subject to the following