GF

NOTES AND QUERIES.

S. C. GOULD,

"

Editor.

Force, the physical offspring of the Infinite Mind."- GEORGE STEARNS.

VOL. XIV.

APRIL. 1896.

No. 4.

Nebular Hypothesis of La Place.

In response to the request of "RADIUS" (Vol. XIV, p. 60) we reprint the following extracts from La Place's "Système du Monde," giving the Nebular Hypothesis as he propounded it. The translation is by J. Pond, F. R. S., London, 1809. These extracts are all that the author wrote on this theory (Vol. II, bk. v, ch. vi; bk. Iv, ch. ix):

First extract. However arbitrary the system of the planets may be, there exists between them some very remarkable relations, which may throw light on their origin; considering them with attention, we are astonished to see all the planets move round the sun from west to east, and nearly in the same plane; all the satellites moving round their respective planets in the same direction, and nearly in the same plane with the planets. Lastly, the sun, the planets, and those satellites in which a motion of rotation has been observed, turn on their own axes, in the same direction, and nearly in the same plane as their motion of projection.

A phenomenon so extraordinary is not the effect of chance; it indicates a universal cause which has determined all these motions. To approximate to the probable explanation of this cause, we should observe that the planetary system, such as we now consider, is composed of seven planets and fourteen satellites. We have observed the rotation of the sun, of five planets, of the moon, of Saturn's rings and of his farthest satellite; these rotations, with those of revolution, form together thirty direct movements in the same direction. If we conceive the plane of any direct motion whatever, coincide at first with

1 Uranus, discovered March 13, 1781; Neptune, discovered September 23, 1846.

that of the ecliptic, afterwards inclining itself toward this last plane, and passing over all the degrees of inclination, from zero to half the circumference, it is clear that the motion will be direct in all its inferior inclinations to a hundred degrees1, and that it will be retrograde in its inclinations beyond that; so that by the change of inclination alone, the direct and retrograde motions of the solar system can be represented. Beheld in this point of view, we can reckon twenty-nine motions, of which the planes are inclined to that of the earth, at most one-fourth of the circumference; and supposing their inclinations had been the effect of chance, they would have extended to half of the circumference, and the probability that one of them would have exceeded the quarter would be 1 -, or 536870911. It is then extremely probable that the direction of the planetary motion is not the effect of chance, and this becomes still more probable if we consider the inclination of the greatest number of these motions to the ecliptic is very small, and much less than a quarter of a circumference.

536870912.

Another phenomenon of the solar system, equally remarkable, is the small eccentricity of the orbits of the planets and their satellites, while those of comets are much extended. The orbits of the system offer no intermediate shades between a great and small eccentricity. We are here again compelled to acknowledge the effect of a regular cause; chance alone could not have given a form nearly circular to the orbits of all the planets; that must also have influenced the great eccentricity of the orbits of the comets, and what is very extraordinary, without having any influence on the direction of their motion; for, in observing the orbits of the retrograde comets as being inclined more than one hundred degrees to the ecliptic, we find that the main inclination of the orbits of all the observed comets approaches nearly to one hundred degrees, which would be the case if the bodies had been projected at random.

Thus, to investigate the cause of the primitive motion of the planets, we have given the five following phenomena :

1. The motions of the planets in the same direction, and nearly in the same plane.

2. The motion of the satellites in the same direction, and nearly in the same plane with those of the planets.

3. The motion of rotation of these bodies, and of the sun in the same direction as their motion of projection, and in planes but little different.

4. The small eccentricity of the orbits of the planets and of their satellites.

5. The great eccentricity of the orbits of the comets, although their inclinations may have been left to chance.

1 Ninety degrees by our mode of reckoning.

Buffon is the only one whom I have known, who, since the discovery of the true system of the world, has endeavored to investigate the origin of the planets and their satellites. He supposes that a comet in falling from the sun, etc., etc. This hypothesis, then, is far from accounting for the preceding phenomena. Let us see if it be possible to arrive at their true cause.

Whatever be its nature, since it has produced or directed the motion of the planets and their satellites, it must have embraced all these bodies; and considering the prodigious distance which separates them, they can only be [it could only have been?) a fluid of immense extent. To have given in the same direction a motion nearly circular around the sun, the fluid must have surrounded that luminary like an atmosphere. This view, therefore, of planetary motion, leads us to think that in consequence of excessive heat, the atmosphere of the sun originally extended beyond the orbits of the planets, and that it has gradually contracted itself to its present limits, which may have taken place from causes similar to those which caused the famous star that suddingly appeared in 1372, in the constellation of Cassiopeia, to shine with the most brilliant splendor during many months.

The great eccentricity of the orbits of the comets leads to the same results; it evidently indicates the disappearance of a great number of orbits less eccentric, which indicates an atmosphere round the sun, extending beyond the perihelion of observable comets, and which, in destroying the motion of those which they have traversed in a duration of such extent, have reunited themselves to the sun. Thus we see that there can exist at present only such comets as were beyond this limit at that period. And as we can observe only those which in their perihelion approach near the sun, their orbits must be very eccentric; but, at the same time, it is evident that their inclinations must present the same inequalities as if the bodies had been sent off at random, since the solar atmosphere has no influence over their motions. Thus, the long period of the revolution of comets, the great eccentricity of their orbits, and the variety of their inclinations, are very naturally explained by this atmosphere.

But how has it determined the motions of revolution and rotation of the planets? If these bodies had penetrated this fluid, its resistance would have caused them to fall into the sun. We may then conjecture that they have been formed in the successive bounds of this atmosphere by the condensations of zones, which it must have abandoned in the plane of its equator, and in becoming cold have condensed themselves towards the surface of this luminary, as we have seen in the preceding book. [See next extract.] One may likewise conjecture that the satellites have been formed in a similar way by the atmospheres of the planets. The five phenomena explained above

naturally result from this hypothesis, to which the rings of Saturn render an additional degree of probability.

Whatever may have been the origin of this arrangement of the planetary system, which I offer with that distrust which everything ought to inspire that is not the result of observation or calculation, it is certain that its elements are so arranged that it must possess the greatest stability, if foreign observations [influences?] do not disturb it.

Second extract. All the atmospheric strata should take, after a time, the rotary motion common to the body which they surround. For these strata against each other, and against the surface of the body, should accelerate the slowest motions, and retard the most rapid, till a perfect equality is established among them. In these changes, and generally in all those which the atmosphere undergoes, the sum of the products of the particles of the body and of its atmosphere, multiplied respectively by the area which their radii vectores projected on the plane of the equator describe round their common center of gravity, are always equal in time. Supposing, then, that by any cause whatsoever, the atmosphere should contract itself, or that a part should condense itself on the surface of the body, the rotatory motion of the body, and of its atmosphere, would be accelerated, because the radii vectores of the area dcscribed by the particles of the primitive atmosphere becoming smaller, the sum of the product of all the particles by the corresponding area could not remain the same unless the velocity of the rotation augments.

The point where the centrifugal force balances gravity, is so much nearer to the body in proportion as its rotary motion is more rapid. Supposing the atmosphere extends itself as far as this limit, and that afterwards it contracts and condenses itself from the effects of cold at the surface of the body, the rotatory motion would become more and more rapid, and the farthest limit of the atmosphere would approach continually to its center; it will then abandon successively in the plane of its equator fluid zones, which will continue to circulate round the body because their centrifugal force is equal to gravity. But this equality not existing relative to those particles of the atmosphere distant from the equator, they will contiuue to adhere to it. It is probable that the rings of Saturn are similar zones abandoned by its atmosphere. These two extracts contain all that La Place has to say on the Nebular Theory, on which later writers have speculated so much. George Stearns, in his work, "The Pericosmic Theory," substantiates Pa Place's hypothesis; indeed, the Pericosmic Theory is the mathematical commentary of the solar system based on this theory. Herbert Spencer, in his essays, " Illustrations of Universal Progress," devotes 61 pages (chapter IX) to a discussion of the hypothesis. See an able and interesting memoir on the Nebular Hypothesis by avid Trowbridge, in American Journal of Science, November, 1864. Iso, "Cosmic Philosophy," by John Fiske, Vol. I, chapters v and vi.

JACOB BEHMEN'S UNFOLDMENT OF THE OMNIFIC NAME - JEHOVAH. "The ancient Rabins among the Jews have partly understood the Name; for they have said that this Name is the Highest and most Holy Name of God; by which they understand the working Deity in Sense; and it is true, for in the working sense lies the true life of all things in Time and in Eternity, in the Ground and Abyss; and it is God himself, namely, the Divine working Perceptibility, Sensation, Invention, Science, and Love; that is, the true understanding in the working unity, from which the five senses of the true life spring.

"Each Letter in this Name intimates to us a peculiar virtue and working, that is, a Form in the working Power.

For I is the Effluence of the Eternal indivisible Unity, or the sweet grace and fullness of the ground of the Divine Power of becoming something.

H

E is a threefold I, where the Trinity shuts itself up in Unity, for the I goes into the E, and joineth IE, which is an outbreathing of the Unity itself.

E

H is the Word, or breathing of the Trinity of God.

H

O is the Circumference, or the Son of God, through which the IE and the H, or breathing, speaks from the compressed Delight of the Power and Virtue.

T is the joyful Effluence from the breathing, that is, the proceeding Spirit of God.

V

A is that which is proceeded from the power and virtue, namely, the Wisdom; a Subject of the Trinity; wherein the Trinity works, and wherein the Trinity is also manifest.

A.

"This Name is nothing else but a speaking forth, or expression of the Threefold working of the Holy Trinity in the Unity of God."

II.

Behmen, as an inspired Seer, believes in the essential unity of things, and sees all truth mirrored not only in Nature and the Soul of Man, but in language also. He has great confidence in the mystical import of words and even of letters. His paraphrase of the Lord's Prayer, on this ground, is a great curiosity. It is as fanciful as can be imagined, and yet singularly striking, and sometimes becutiful.