Jtme 13, 1878] 



NATURE 



185 



from universal space, and thus the temperature in its interior 

 is gradually increased to an immeasurable extent. Then the 

 moment arrives when the exterior crust can no longer resist the 

 rising pressure of the inclosed masses, which have, of course, 

 become gaseous. An explosion must result. The greater part 

 of the mass which is converted into gas is dispersed over a great 

 space, and thus by far the greater part of the accumulated heat 

 is converted into gravitation and force of rotation o ithe dispersed 

 masses. Now the second portion of the solar period begins, 

 which, as a process of condensation of cosmical nebulae and 

 subsequent slow cooling of the bodies formed by this condensa- 

 tion, has been frequently discussed since the days of Laplace. " 



This is Ilerr Loschmidt's idea of the typical course of a cos- 

 mical period, if fully developed according to the laws of heat. 

 But he thinks that it is highly probable that this full develop- 

 ment can be but rarely realised in the case of a solar system, 

 since the duration of the heat-absorption will generally find a 

 premature end in the impossibility of the external crust resisting 

 the enormous pressure of the inclosed gases until the maximum 

 of temperature is arrived "at. " Upon our sun, for instance, in 

 a state of equilibrium of temperature, the surface temperature 

 would be — 140° C, while at a depth of half a (German) 

 mile we already would find a temperature of 3,000° C. Here 

 all known substances would be in a state of liquid incandescence. 

 The solid crust could therefore not be thicker than half a 

 (German) mile. In this case, therefore, the typical course 

 described would evidently be interrupted prematurely by an 

 explosion. 



"The consequences of a solar eruption of this kind are natu- 

 rally very different under different] conditions. Thus with a 

 comparatively small accumulation of heat and corresponding low 

 tension, the result would be simply the return to incandescence 

 of a dark heavenly body, while with greater concentration of 

 heat some portions [may be separated from the principal mass 

 and carried to great distances, where, forming themselves into 

 planets, they would revolve round the principal mass in elliptical 

 orbits. This theory, therefore, easily explains the origin of 

 planets, like those of our system, and the manner in which they 

 were carried to their respective places and are provided with 

 '.heir forces of rotation and revolution, and also how after all in 

 the principal solar mass a quantity of heat would remain, which 

 would cause a far higher temperature upon its surface than exists 

 at present upon our sun. The principal solar mass would thus 

 be again enabled to radiate light and heat to its planets and into 

 the universe, until again the moment of solidification and re- 

 beginning of absorption of heat has arrived. The total result 

 under the most varying circumstances always remains the same : 

 periodicity of the dynamical solar phenomena. 



" If finally we look for proofs for our theory in the heavens, 

 we direct our attention to dark bumt-out suns on the one hand 

 and to suddenly appearing new suns on the other. It is strange 

 that modem times have given examples of both classes of pheno- 

 mena. As a representative of the first class we have the dark 

 companion of Sirius, calculated in advance by Bessel from the 

 disturbances, and actually seen by A. Clark and Pond In 1862. 

 This enormous mass has only just been rendered visible by the 

 most powerful instruments, although it is nearly seven times the 

 size of our sun. A second example is the companion of Procyon 

 which, though calculated with certainty, has not yet been seen 

 on account of its still greater darkness. Examples of the other 

 class we have in the well-known new stars of Tycho Brahe and 

 Kepler, besides the new star in Corona of 1866 and the one 

 recently seen by Schmidt and others in Cygnus (December, 

 1876). In both these latter cases eruptions of incandescent 

 hydrogen were proved beyond doubt by spectral observations." 



THE METEOR 



A METEOR of unusual brilliance was seen of the " fire-ball" 

 ■^ type on Friday night by several correspondents. All agree 

 that the time was about 9.50, the moon at the time being in her 

 second quarter, and about 30° above the horizon in thewest-south- 

 west. At Twickenham its observed course was from south-west to 

 north-west passing the azimuth of the moon at the time 69° from 

 south to west, at an altitude of about 14°, its path being nearly 

 parallel to the horizon, or declining very slightly towards its 

 disappearance, which was sudden, at 9h. 52m. 30s. Greenwich 

 mean time. Colour, bright emerald green ; apparent diameter, 

 about one-third of that of the moon, this being the greater 

 diameter of the, elliptical figure. The light thrown by the 



meteor in this locality was decidedly green. Mr. Lecky, 

 writing from the Scientific Club, states that the course of 

 the meteor was about 90° below the moon, its motion very slow, 

 and it became extinguished rather suddenly, without any appa- 

 rent bursting, when it had passed about the same distance to the 

 north of the moon. The meteor appeared to Mr. Lecky to be 

 about the same size as the moon. Mr. L. J. Whalley saw it 

 from the Brompton Road. Facing west he saw it pass from 

 south to north, its path being inclined downwards at a few 

 degrees to the horizon, and its altitude about 30". The fore-part 

 appeared rounded in shape, and of a bright green colour (like 

 nickel sulphate), whilst the tail tapered off, and was of a red to 

 a purplish tint. 



Mr. Walter Fowler saw it from Cambridge. Its path, he 

 states, was from south to north, almost parallel with the horizon, 

 with a slight declination northwards, IDuring its course, which 

 lasted about twenty seconds, it emitted innumerable sparks 

 variegated in, colour. 



Another correspondent saw it from London Street, Green- 

 wich. Its apparent altitude, he states, was about 28° or 30° 

 above the western horizon, and it passed horizontally over the 

 tops of the houses in a direction about two points to the west of 

 north. He observed it for about three seconds. It appeared 

 in passing under the moon to be about 6° or 8° underneath her 

 lower limb, and about the same degree of brightness and equal 

 to it in size. The meteor, he states, had a tail about equal to 

 six or seven diameters of its nucleus ; the central part of the 

 tail and the nucleus were of a pale orange hue and fringed with 

 violet rays. The tail was in the line of motion, and was not a 

 perfect cone, but appeared to expand into a fin-like form at the 

 extremity. 



Mr. F. J. Richardson, of Dimchurch, near Rugby, observed 

 the meteor, "of considerable size," cross the sky, apparently 

 about 30° above the horizon. The direction of its path was 

 from south to w-jst, and its colour appeared a mixture of orange 

 and green. It remained visible for about thirty or forty seconds, 

 and then suddenly disappeared. 



Mr. R. Langdon, writing from Silverton Station, Devon, states 

 that it moved slowly towards Ursa Major, and exploded a little 

 beyond that constellation. Its colours were, first, very pale blue 

 (nearly white), then deep blue, and finally, the several fragments 

 after explosion were blood-red. Dr. Morison saw it from 

 Jersey. When first seen it was about 30" from the zenith in a 

 direction nearly due north. The diameter of its disc, which was 

 apparently circular, was rather more than half that of the full 

 moon, which it far surpassed in brilliancy, shining with a beauti- 

 ful white light. The meteor descended towards the horizon, 

 leaving a very faint luminous trail behind it, and was lost to 

 sight, while still remaining entire, behind a high wall. It was 

 altogether visible about thirty seconds. 



Our Paris correspondent writes that a splendid meteor was 

 seen in the department of Aisne and at Versailles about ten 

 o'clock in the evening, travelling westwards at a small altitude. 

 It was in diameter about one -sixth that of the moon, the brilliancy 

 admirable, and the tail four or five times the length of the moon's 

 diameter. No noise was heard. 



Mr. Denning, of Bristol, writing to the Times, states that the 

 meteor had a very long path, almost horizontal, from east to 

 west, which it traversed with a gradual motion, casting off a 

 short train of sparks as it sailed along, and showing sensible 

 variations in the brilUancy of its pear-shaped nucleus. The 

 position of the observed part of its path was noted from l° above 

 the star Spica Virginis to 6° above the moon, but to include the 

 whole extent of its visible course the line must be extended in 

 each direction, and have a length of at least 75° from, say, 

 slightly below Alpha Librse to slightly above Alpha Leonis, 

 running almost parallel with the ecliptic. The meteor was con- 

 siderably brighter than Venus, and perhaps equal to a body one- 

 fourth of the moon's diameter. Mr. H. Middleton Rogers 

 states that while walking along a footpath close to Knole Park, 

 he saw it passing apparently from south to north, very nearly 

 parallel to the horizon, with a very slight declination towards 

 the north. When he first saw it it was about 5° from the moon, 

 (taking the moon's diameter roughly at half a degree.) It passed 

 slowly\long about 3° below the moon, or about 30° above the 

 horizon, and continued its course for about 20° further towards 

 the north, when it suddenly disappeared. The light was of a 

 very pale gi-een, as nearly as possible like the light of a glow- 

 worm highly intensified. As it passed under the moon its 

 brilliancy^'caused the moon to look of a muddy yellow colour— 



