738 EDITORIAL 
union by collision, give rise to retrograde rotations, because the 
orbital velocities of the inner bodies are the greater, and this has 
been regarded as a serious objection to the aggregation of the 
earth and all but the outermost planets from a ring of discrete 
matter of the type of the Saturnian rings as distinguished 
from an aggregation from a gaseous ring after the manner of the 
Laplacean hypothesis. (Faye, Sur 2 Origine du Monde, 1896, 
pp. 165, 270-281). The writer has, however, pointed out that, 
if the aggregation of such discrete matter took place through 
the development of eccentric orbits which cut each other’s paths 
and thus led to collision, the bodies pursuing the outer orbits 
would be moving faster at the points of collision than those pursu- 
ing the inner orbits, and that on the average the rotations result- 
ing from the collisions would be direct (A group of Hypotheses 
Bearing on Climatic Changes, JouRNAL OF GEoLoey, Vol. V, No. 
7, 1897, p. 668). The new planet furnishes us with a concrete 
illustration of the principle urged. It has been estimated that, 
at the time of its greatest approximation, the new planet will be 
moving 500 feet per second faster than the earth, a figure which 
is doubtless subject to considerable correction from fuller data. 
The discovery of this rather erratic body has renewed the pre- 
vious suggestion that small planetoids may not be rare in other 
tracts than the asteroidal belt between Mars and Jupiter. It will 
doubtless have some influence in reopening for renewed con- 
sideration the mode of aggregation and the past history of the 
solar system, a consideration which has been rendered opportune 
by the serious, if not fatal, objections to the accepted gaseous 
hypothesis which have arisen from the application of the kinetic 
theory of gases. TGs ©, 
