Abstract
There exist today only two widely accepted theories of the origin of the solar system, and hence of our earth - the Planetesimal Hypothesis of the late Dr. T.C. Chamberlin and Prof. F.R. Moulton, both of the University of Chicago; and the Tidal Theory of Sir J.H. Jeans and Dr. Harold Jeffreys. In the past it has seemed to many scientists on this side of the Atlantic that these two great English thinkers had ignored unduly the researches of Professors Chamberlin and Moulton, although it was considered that the Tidal Theory was largely an outgrowth of the theories developed by the Chicago scientists.