SCIENCE. 



179 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for opinions expressed 

 by his correspondents. No notice is taken 0/ anonymous communi- 

 • cat ions.] 



To the Editor of " Science ■" 



PRIMITIVE STAGES OF COSMICAL EVOLU- 

 TIOxN. 



Some correspondence which has recen'ly appeared in 

 your columns seems to render it proper to offer a brief 

 synopsis of my conception of the primitive modes ot ex- 

 istence of cosmical matter. Supposing luminous cosmi- 

 cal matter to be intensely heated, there is no good reason 

 for assuming this to be absolutely a first condiuon. It is 

 undoubtedly a i emote and primitive condition, which 

 may be assumed as a stage from which cosmical develop- 

 ment proceeds. But, in the light of recent science, we 

 may reasonably seek for earlier stages at which cosmical 

 matter existed in a cold and non-luminous state. In these 

 stiges we may conceive it either as atomically sub- 

 divided and dissociated, or as partly in a condition of 

 molar aggregation, and perhaps of chemical combination. 

 I am inclined to think, wiih Laplace and Kant, that space 

 is abundantly stocked with cosmical matter in a crude 

 and unformed state. I see no grour d for assigning any 

 limit to the state of subdivision in which some of it 

 may exist. I see no satisfactory grcund for assuming as 

 Macvicar and others have done, that it emerges from an 

 ethereal condition, nor for denying it. I do not imagine 

 it to possess a temperature different from that ot the 

 space in which it floats — if, indeed space, which is net 

 conditioned by matter, can be said to possess a property, 

 which we only know as an affecton of matter. 



But there is a principle of gravitation in the universe, 

 however we may explain it, which is ever beginning the 

 aggregation of the ultimate elements of cosmical matter, 

 and ever uniting ihese aggregations into masses larger 

 and larger. We have made the acquaintance of some of 

 these masses, large and small, in meteoric stones and 

 millions of meteoroids, which become kindled only by 

 friction with our atmosphere. It has been shown that 

 several metecroidal trains identify themselves with well- 

 known cometary existences. It has been suggested that 

 a rain of cosmical matter has pelted the minute satellites 

 of Mars until the angular orbital motion of the inner one 

 exceeds the axial motion of the planet. The collisions 

 of molecules and masses must result in the evolution of 

 heat. This, within certain limits of temperature, would 

 promote the chemical union of atoms previously disso- 

 ciated. But the impact of larger masses and groups of 

 masses and molecules would undoubtedly develop suffi- 

 cient heat to vaporize matter, and even to reproduce a 

 state of dissociation. Such events would characterize 

 the history of any vast region of space in which cosmical 

 atoms should h&ve become relatively approximated. They 

 are in process ot falling together. This is the condensa- 

 tion of the cosmical swarm. It may proceed, as Sir 

 William Herschel conceived, until the successive stages 

 of nebular condensation have been passed, when the 

 swarm arrives at the condition of a sun. But it is well- 

 nigh impossible for two cosmical masses to come to- 

 gether without producing rotation. The constituent por- 

 tions of a nebula must ptobibly rotate, and the nebula 

 as a whole must, in most cases, exist in a state of rota- 

 tion. Such a nebula was the starting point ot Laplace, 

 and was recognized as an actual contingency by Sir 

 William Herschel. 



But I do not conceive a fully formed and characteristic 

 nebula as necessarily in a state of complete gaseity. The 

 perpetual collision of hard parts might vaporize sufficient 

 matter to occupy the intervening spaces and afford the 

 characteristic spectral results. 



As longas the nebula remains in processof condensation 

 through central gravitation, the evolution of heat must 

 continue. But there is a juncture at which rise of tem- 

 perature must cease. That is reached when the elastic 

 torces equilibrate the attractive. From this point, con- 

 densation developes heat, but seme more is lost than is 

 acquired, ami the mass continually subsides in tempera- 

 ture. It is only the loss of an excess of heat which now 

 permits the progressing condensation. Cooling is the 

 limiting condition of condensation ; and to assert a rising 

 or a constant temperature is to assume that a condition 

 may be surpassed by the effect of that which it condi- 

 tions and measuies. It is a virtual denial of the con- 

 servation of energy and of the equation of cause and 

 effect. 



In this view of cosmical beginnings, nebular heat is 

 preceded by motion, and the cause of motion is what 

 we call gravity. If, ?s Le Sage maintained, gravity is 

 only the effect of the impact of a storm of ultramundane 

 corpuscles, then our explanation ends at last in motion 

 for which we canr.ot invoke gravity as an ultimate phy- 

 sical cause. Metaphysically speaking, such must be the 

 issue of all explanations. There is a necessary ultima 

 thule in the realm of though'. We are no nearer an 

 absolute explanation at one stage of cosmical develop- 

 ment than at any other The remotest term reached 

 must always stand scien'ifically unexplained. 



I began by supposing luminous nebular matter in- 

 tensely heated. There are many indications that such is 

 its condition. The bright spectral lines and the analogy 

 of the envelopes of the solar snd stellar bodies are 

 strongly suggestive. The rational continuity of cosmical 

 develorment, leading our thoughts backward from an in- 

 crusted world through all conceivable stages, to an in- 

 candescent vapor or possibly gas, enforces the conviction 

 of high nebular temperature. But, on the contrary, the 

 very limited number of nebular bright lines spectroscopi- 

 cally revealed proclaims a fundamental condition widely 

 d fferer.t from that in the sun and fixed stars. It might be 

 suggested that this indicates not only elemental dissocia- 

 tion, but an ulterior resolution, as Lockyer maintains, into 

 one or two sole sorts of world-stuff; but it may also be 

 suggested that the phenomenon is so divergent from the 

 results of any terrestrial verifications that we are left 

 without any substantial ground for inference. The 

 nuclei of comets give also a few bright spectral lines. 

 When the comet is near its perihelion it is not difficult to 

 admit, in some cases, that the speclrum reveals a volati- 

 lized condition ; but when a body so tenuous as to trans- 

 mit star-light has retired from perihe ion, it is difficult to 

 believe that a gaseous condition is still the effect of high 

 incandescence. The ident ticaticn of cometary and cold 

 mtteoioidal trains, if it has truly been done, throws 

 doubt on the assumed heat of even the nuclear portions 

 of a comet remote from the sun ; and yet even here it is 

 supposable that perpetual collisicn of cold hard parts dis- 

 engages sufficient heat to create a common gaseous med- 

 ium. Finally, the meteoric streak of light left semttimes 

 fifteen to thirty minutes after the fall and dissipation 

 of the meteor, cannot be a case cf heated luminosity. 

 Heat vaporizes the meteoroid ; but it is then a train of 

 minutely divided particles exposed to almost instantan- 

 eous refrigeration. A few grains of matter strewn along 

 a path twenty miles In extent, in the cold atmosphe-re, 

 cannot retain luminosity as a consequence ot lrgh tem- 

 perature. We might cite the streamers of the aurora 

 borealis, and the Geisslerian discharges, and Crooke's 

 radiant matter, and the general phenomena of phosphor- 

 escence as further reminders that intense heat is not the 

 only cause of luminosity, and suggestions that nebular 

 light may net be exclusively the light of thermal incan- 

 descence. 



Alexander Winchell. 



V 



University of Michigan, April %, 1881. 



