408 THOMAS C. CHAMBERLIN 
planetesimals. If they are planetesimals left over from the forma- 
tion of the planets, they are surely old enough to have grown to 
the largest practicable sizes; but, in spite of this, they are certainly 
quite small. If they have had a more recent origin, they should still 
represent normal growth. In any case, they add their testimony 
to the smallness of planetesimals.* 
57. The restudy of cosmological processes led. to a new view 
as to the relations of the erratic elements of the solar system, 
the meteors, meteorites, and comets, to the normal elements, the 
planets, planetoids, planetesimals, satellites, and satellitesimals, 
to the effect that they were all formed by the same type of dynamic 
action, save that the former were given erratic orbits, while the 
latter were given concurrent orbits. The ways in which this 
difference arose are given in the original discussion. These give a 
unitary view to the whole solar system. Now under them, chon- 
drules are interpreted as aggregates of stony and metallic precipi- 
tates from solar gases, growing in a manner similar to that of the 
planetesimals. If so, the sizes of chondrules and planetesimals 
should be about the same. Chondrules vary in size from walnuts 
down to dust particles, millet seed being mentioned as representa- 
tive. Their history differs in some features from that of meteor- 
ites, and they might be called meteoresimals to distinguish them. 
They seem to be immensely more numerous than meteorites; 
probably at least a hundred million of these meteoresimals “burn 
out” in the upper air as “‘shooting stars” for every meteorite that 
reaches the ground. 
58. Meteorites proper are interpreted as fragments of erratic 
bodies disrupted by the extremes of heat and cold they suffer at 
the two ends of their very elliptical orbits. The parent bodies 
are held to have been formed by the aggregation of precipitates in a 
way similar to the aggregation of planetoids (No. 49 above), 
except that the original material was given very diverse and 
elliptical orbits.2 Under this view, it is not the meteorites but the 
chondrules that are analogous to the planetesimals. 
«“The Zodiacal Planetesimals,” Article XIII, Jour. Geol., Vol. XXVIII (1920), 
DaO72. ; 
2 “The Testimony of the Aberrant Bodies of the Solar System,” zbzd., pp. 696-701. 
3 [bid., pp. 697-08. 
