406 THOMAS C. CHAMBERLIN 
type. In most cases, however, the nuclei were unable to hold any 
appreciable amount of such gases. Some of the smallest could not 
hold the hot vapors of even stony and metallic substances. This 
would have led to their complete dissolution but for the fact that, 
on emergence from the sun into interplanetary space, they promptly 
condensed into clouds of precipitates and these soon gathered into 
precipitate aggregates. ‘These, being much larger and less active 
than the molecules of the previous vapors, were held under control 
and collected into planetoids.* 
50. The formation of precipitates and precipitate aggregates 
of stony and metallic substances apparently played an important 
part in the condensation of planetary nuclei. As such precipitates 
appear to be forming. now in the photosphere of the sun, it is 
assumed that they would be formed freely in solar gases projected 
into planetary space. Such aggregates would act as Brownian 
particles and the condensation would not be strictly gaseous. If 
the nuclei later passed into the liquid state, crystalline and con- 
cretionary aggregates would probably form and give rise to a 
solid-liquid Brownian mixture. The descent was therefore that of 
Brownian mixtures of different types rather than simple gaseous 
condensation.” 
51. Each planetary nucleus must have inherited internal 
motions from its solar state and from its ejection, and this must 
have promoted cooling and precipitation during the first critical 
stages. Later, convectional movements were added and con- 
tinued the precipitation. The inherited motions must have been 
more or less asymmetrical and this tended to give asymmetry to the 
core as it solidified. 
52. The inherited motions and the sifting processes were sources 
of hazard to each small nucleus. Probably the smallest plane- 
toids and satellites now seen were the smallest that could be formed 
in this way. The spheres of control of even small nuclei were, 
however, surprisingly large, and this was doubtless the saving 
« “The Physical Phases of the Planetary Nuclei during Their Formative Siaee 
Article XII, Jour. Geol., Vol. XXVIII (1920), pp. 492-08. 
2““The Formation of Precipitates and of Brownian Mixtures,” zbid., pp. 489-92. 
3“‘The Motions Inherited from the Solar Eruption,” zbid., pp. 483-87. 
