78 



♦ KNOWLEDGE ♦ 



[February 1, 1888. 



Aryans who had first spread eastwards extending themselves 

 westwards beyond Asia Slinor to Greece and Italy, while of 

 the Aryans who had first spread westwards, some extended 

 themselves northwards into the Danish peninsula, and then 

 westwards and southwards over the British Isles, France, 

 Spain, and even Africa (where the Kabyles ai-e distinctively 

 Aryan) and others passed from parts of Southern Germany 

 eastwards again. On such points there must ever remain 

 much doubt, but the evidence grows clearer and stronger, 

 year by year, that the real centre of dispersion was in 

 North-eastern Europe, and not in Central Asia. 



MATERIAL OF THE UNIVERSE. 



[Concluded from page 58.) 



TOUCHED in my last on the relative masses 

 of the various members of the solar system, 

 and in so doing considered in a sense their 

 relative might, for on account of that myste- 

 rious power which matter possesses of attract- 

 ing matter we measure the strength of each 

 orb in the universe by its quantity of matter, 

 to which its attractive action at any given 

 distance is strictly proportional. 



But there are other circumstances by which the import- 

 ance of the several planets, measured by reference to the 

 sway which each is cap.xble of exerting on surrounding 

 matter, is influenced, if not directly determined. 



For example, consider the power which the sun has of 

 communicating velocity to matter drawn to his sui-face from 

 a distance. In this there is not only evidence of attractive 

 might, but also of potentialitj' in regard to other attributes 

 not less important to the sun regarded as the chief orb of 

 the solar system. For the sun's light and heat, as well as 

 other qualities which he possesses as a radiant orb, depend 

 on this effect of his attractive energy. We do not, indeed, 

 at present attach much weight to a theory once in vogue, 

 according to which the sun's light and heat were regarded 

 as due to the actual impact of meteoric bodies drawn 

 toward him in countless millions from outer space. But 

 the theory now generally accepted, according to which the 

 sun's heat is the thermal equivalent of the mechanical pro- 

 cess of contraction, going on constantly in consequence of 

 the sun's powerful attractive action on the materials of his 

 own globe, does in reality quite as definitely attribute his 

 light and heat to his attractive energy as did the old 

 meteoric theory ; and we may take the velocity he is capable 

 of generating in bodies drawn to him from great distances 

 as aflbrding a measure of his power — one might almost say 

 his vitality — in this respect, quite as confidently as though 

 the direct impact of such indrawn matter stirred his surface 

 to intense heat, and so caused it to glow with intense 

 lustre. 



Now assuming as I do throughout my book (still in the 

 stage of growth) that the sun's distance is 92,780,000 miles, 

 which I consider probably far nearer the truth than 

 Newcomb's ninetj'-two and one-third millions, I find that 

 his mass amounts to 330,500 times the earth's, and that the 

 velocity with which matter drawn to his surface from an 

 indefinitely gi-eat distance would impinge vertically upon that 

 surface is no less than 382'57 miles per second. It is hardly 

 necess;iry to say that none of his dependent orbs compares 

 with him in this respect. If a body were let fall upon 

 Jupiter from an indefinitely great distance, being drawn to 

 Jupiter's surface by that planet's sole attraction, the velocity 

 of impact would be but 37'37 miles per second. In Saturn's 



case the velocity would be 22-58 miles per second ; in 

 Neptune's [case 1372 miles; in the case of Uranus 13"25 

 miles; in the earth's G-913 miles (this represents the 

 velocity of seven miles per second with which .lules Verne's 

 Columbiad had to shoot forth those venturesome travellers 

 to the moon) ; in Venus's case the velocity of impact, 

 always supposing each planet left alone to generate the 

 greatest possible velocity, would be only 6 '218 miles per 

 second: in the case of Mars it would be 3'179 miles; in 

 that of Mercury 2-901 ; while lastly, our small companion 

 planet, the moon, if left to do its best alone on matter 

 approaching it from a very great distance, could not 

 generate a greater velocity than 1-1:82 mile in each second 

 of time — though this, by the way, is a considerable velocity, 

 being about four times the velocity with which a cannon- 

 ball leaves the mouth of the best cannon men have yet been 

 able to construct. 



Bat no planet is able to exercise its control on an 

 approaching orb in this undisturbed fashion. There is 

 only indeed a comparatively limited region within which the 

 rule of a planet is superior to that of all other bodies, even 

 including the sun. Each planet has in this sense a special 

 domain, the limits of which are determined by the considera- 

 tion that whereas a bodj- outside those limits is drawn more 

 strongly toward the sun than toward the planet, within 

 them the reverse holds, and though it may be but for a 

 time that the planet exerts superior influence, the influence 

 of the planet on a body so situate is greater than that of 

 the sun or than the combined influence of the sun and all 

 other bodies whatsoever. 



The sun, however, is the only orb whose power in 

 diminishing the control of the several planets over sur- 

 rounding space need be considered, all other influences 

 being relatively insignificant. He aflects the rule of planets 

 in two distinct ways : — First, by his direct power in draw. 

 ing matter toward him more strongly than any planet can, 

 unless the body is comparatively close to its surface ; and 

 secondly, by communicating such velocities to bodies mov- 

 ing within the solar system that even wlien they enter the 

 domain of a planet they remain within it but a short time. 

 Since his power in both respects depends on his distance, or 

 rather on the planet's distance from him, we find the outer 

 planets set in a relatively higher position as independent 

 rulers than the mere superiority of their mass would imply; 

 nay, the outermost of the outer family is set absolutely 

 higher in regard both to extent of domain and influence 

 within such domain than even the two chief planets Jupiter 

 and Saturn themselves. 



I have calculated the extent of the domains of the several 

 planets, and the velocities with which matter entering those 

 domains would pass through them independently of the 

 action to which they are exposed during their passage. The 

 results are, I think, interesting, presenting, as they do, the 

 relative sway of the difierent members of the solar system in 

 a somewhat new light. 



All the four terrestrial planets have domains very 

 limited in extent compared with those of the four outer 

 planets. The spherical domain of Mercury has a diameter 

 of only 32,000 miles ; and as bodies which chance to pass 

 through it have velocities ranging up to no less than 42 

 miles per second, ^Mercury's chance of much influencing 

 bodies passing near him is very small. Oiir own moon, 

 though she has less than a fifth the mass of Mercury, has 

 much more power in this respect, her domain being about 

 36,000 miles in diameter, while the greatest velocities of 

 bodies passing near her are but 26 miles in a second. 

 Tenus has a domain 106.000 miles in diameter, and at her 

 greater distance from the sun the maximum velocity of 

 passing bodies is reducel from the 42 miles per second 



