DIASTROPHISM AND THE FORMATIVE PROCESSES 699 



cometic features, for a time, and later suffered dispersion into 

 meteors and meteorites. 



If any of these ancestral secondaries had attained a notable 

 size and happened to be disturbed so as to be drawn through the 

 Roche limit of the sun, it might be disrupted and become a clustered 

 group suited to serve as the nucleus of a comet. This, however, 

 would not be likely to occur in many cases, and so appeal is made 

 chiefly to the riving action of cold in the aphelion journey as the 

 dependable cause for the disrupted character of the comets' heads, 

 and the fragmental features which meteorites commonly show. 



2. The second hypothesis assumes that forces of the kinds dis- 

 closed by the observations of Pettit on the solar prominences of 

 May 29 and July 15, 1919,' projected solar gases and precipitates 

 into the outer regions of the sun's sphere of control, where its 

 attraction was feeble, and where the attractions of neighboring 

 stars and star groups were relatively strong. During these outer 

 flights, the pull of some star, group of stars, or other outside source 

 of attraction drew the ejected masses aside from their normal paths 

 sufi&ciently to cause them to swing by the sun on their return and 

 thus be forced to take highly elliptical orbits. The planes of 

 these orbits and the direction of revolution thus generated would 

 be determined by the various deviating attractions, so that a system 

 formed by a large number of such deviations would be very hetero- 

 geneous orbitally. High ellipticity would be a common charac- 

 teristic. The principles that control aggregation, as previously 

 sketched in this series of papers, would apply to the projected 

 matter in all such cases. In so far as this matter retained self- 

 control, it would assemble by the precipitate-aggregate method 

 into clouds of aggregates, and these would usually be still more 

 closely assembled into loosely organized bodies well suited to 

 function as the nuclei of comet-heads. These would be subject to 

 all the vicissitudes of temperature and of alternate absorption and 

 evolution of gaseous material, sketched above, and so display for 

 a time the spectacular features of comets, and ultimately be dis- 

 integrated into meteorites. In so far as the projected solar matter 

 was too highly dispersed for mutual control, it should have passed 



'Asiropkys. Jour. (Oct., 1919), pp. 206-19. 



