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 UNIVERSE

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UNIVERSE

of 160 pounds a speed of over two thousand turns a minute. The rotation of the earth was strong enough to deviate the horizontal axis, which was suspended on a triple wire, six and a half degrees from the prime- vertical. A novel scheme had been tried by Perrot in 18.59. He made a hquid flow through the central orifice of a circular ve.ssel, and rendered the currents visible by means of floating dust. We have to take his word, that the currents were spiral-shaped, and ran counter-clockwise. The experiment was repeated by Tumlirz in Vienna (1908), and its result photo- graphed and compared with theory. While the ex- periments of Hall, Foppl, and Tumlii'z are repetitions of former ones, with improved methods, the next proof of the diurnal rotation is new as an experiment, although forecast in the idea by Poinsot as early as 1851. It was carried out at the Vatican Observatory in 1909. Its principle is that of equal areas described in equal times, applied to a horizontal beam suspended in form of a torsion balance, on which heavy masses can be moved. The shifting of the masses from extremity to centre will make the beam turn faster than the earth; the opposite wiU happen in the rever.se case. The last proof had never been proposed before, and consists in obser\'ing the tliread of the Atwood machine in a telescope. Viewed in the merid- ian, the thread of the falhng weight is seen to come down east of the plumb-line, but viewed in the prime vertical it remains exactly plumb. This experiment was hkewise carried out at the Vatican Observatory in 1912 (see "Specola Vaticana", I, 1911, appendix II, 1912).

Some writers have expressed surprise that Catholic scientists were allowed to take part in the ex-peri- ments, e. g. that Bonfioli, domestic prelate to Pius VI, assisted Guglielmini in measuring the impressions of the balls on the plate of wax (Benzenberg, "Umdre- hung der Erde", 1804, 278), or that Secchi demon- strated the rotation of the earth in Rome "before all the people" (Wolf, "Handbuch", I, Zurich, 1890, no. 262 c). We must remember, however, that what was condemned in a former age was not the experi- ment but a then gi-atuitous assertion.

II. P.\ST AND Future of the World. — The present system of the world has been found, by the greatest scientists, to be in an unstable condition. As it is, it cannot have existed for many milhons of years, nor can it last for many more. NaturaOy, therefore, speculations have arisen, both retrospective and prospective; but speculations they wiU remain. How the world has developed into its pre.sent shape, and how it will pass out of it, science will never tell. Cos- mogony is the accepted name for all the hypotheses on the past (from Kbaiio^, world, and ylyv€<x0ai, to originate). A con-esponding form from the Greek, to designate the speculations on the futm-eof the world, cosmothany (world's death), was used by C. Braun (Kosmogonie, 190.5, X, 346); more correct formations are perhaps: cosmophthory ((pBopi, corruption) or cosmodysy (Si/o-is, occa5!/.s, dechne). World must here be taken in all its narrower or wider meanings, as earth, solar system, stellar system, universe.

A. Cosmogony. — The writer of the article Cos- mogony has well distinguished between mythical. Biblical, and scientific cosmogonies. While confining himself to the first kind, he left the second for the writer of Hexaemeron, and the third for the present article. The term "scientific" is used only for the sake of distinction. No cosmogony can really claim to be a scientific theory or even hypothesis, in the proper sense of a .systematic development of the de- tails from a definite number of assumed jn-inciples, after the manner of the long-accepted atomic theory, for example. .Ml cosmogonies, so far im.agined, have shared in the common fate of being refuted as insuffi- cient or even impossibk'. Proposition and rejection are alike vague and uncertain, and must be so, as

processes of extrapolation from laboratory laws to th^ fabric of the Creator. Cosmogonies may be classified according to the component parts of the word, con- sidering either the various kinds of cosmos, or the variety of origins. The former classification will bring to fight the necessity of some great cosmogony, while the latter wiU prove to be a mere enumeration of possibilities, real or imaginary.

(1) The classification of cosmogonies by worlds may begin with the microcosm of our terrestrial abode and end with the macrocosm of the universe.

(a) The structure of the earth points to a history, the chronological successions of which can be recog- nized, although the span of duration is unknown. The superficial layer, afiotted to the human race, represents the "Quaternary age". Underlying in space, and preceding in time, there are three others, known as the recent formation, the cretaceous and Jurassic formation, and finally the carboniferous and Silurian. Parallel to the latter three ages, the tertiary, secondary, and primary, run the prehistoric ages of the biological kingdom, known as the cainozoic, the mesozoic, and the paleozoic. The mere aspect of the successive layers justifies their names and calls for a terrestrial cosmogony.

(b) No less exiiUcit are the celestial indications of a planetary cosmogony. The five kinds of uniformity in the orbital motions of planets, sateUites, and comets, adduced by Laplace, are not representative of modern cosmography. Laplace knew of only seven planets and eighteen satelUtes, while we can count eight major and some six hundred minor planets and twenty-six satellites. Besides smaller exceptions to Laplace's "uniformities", the singular situation of our own planet must be accentuated. The earth has only one moon, comparable to itself in size, while the inner planets are moonless, and the outer planets are accompanied by more numerous and more minute satellites, Neptune alone forming an apparent excep- tion. The asteroidal and Saturnian rings render the difference between inner and outer planets still more conspicuous. The rapid discovery of puny satellites by photography has brought to light the asteroidal character of these bodies and suggests the conclusion, that the great planets are accompanied bj' zones of pigmy moonlets, in direct and retrograde motion, in striking contrast to the earth-moon system. The latter forms a veritable binary system, the only one in the solar cortege. Far from destroying I,aplace's conchision, the variations and contrasts onlj' confirm the belief in some planetary evolution. Whatever cosmogony may be imagined, it will have to account for the critical position occupied by om' own planet.

(c) Terrestrial and planetary cosmogonies will not satisfy those who look up to systems of higher order, as they are called in Lambert's " Kosmologische Briefe" (1761). The solar system is a mere fragment of creation. Its fundamental plane, or echptic, is replaced in the stellar system by the galaxy, and its planetary revolutions have their equivalent in the I^roper motions of the stars, including our own sun, which is mo\ ing towards the constellation of Hercules. Even tlie difference between slow and swift planets is reflected in the white Helium-stars (6.5 kilometres per second) and the strongly coloured stars (19.3 kilometres). The Jovian and Saturnian sy.stems, with their client globes and rings, have their counter- parts in the solar clusters of the Pleiades and Hyades, drifting each of them along the galactic plane around some unknown centre of gravity. The ecliptic character of the !\Iilky Way is further evidenced by the grouping of the ,\lgol stars and the nonr along its bell, representing stellar <'clipses and collisions. The general condensation of the stars towards the galactic circle, and its lining by the brightest constellations in the heavens, has conveyed the idea of a flattened stellar cumulus. More likely its shape is that of a