the reader will find it set forth at length elsewhere,[17] together with what I conceive to be the only explanation of paleothermal times which will work astronomically—presently to be mentioned. But before I do so, it is pertinent to record two things that have come to my notice since. One is that in rereading Faye’s “Origine du Monde,” I came upon a passage in which it appears that M. Blandet had actually consulted Faye about his hypothesis, and that Faye had shown him its impossibility on much the same grounds as those above referred to; which, however, did not deter M. Blandet from giving it to the world nor De Lapparent from god-fathering the conception. [16] “Abrégé de Geologie,” De Lapparent. [17] “Mars as the Abode of Life,” Macmillan, 1908. Faye, meanwhile, developed his theory of the origin of the world, and by it explained the greater heat and lesser light of paleologic times compared with our own, thus: The Earth evolved before the Sun. In paleologic times the Sun was still of great extent,—an ungathered-up residue of nebula that had not yet fallen together enough to concentrate, not a contracting mass from which the planets had been detached,—and was in consequence but feebly luminous and of little heating effect; so that there were no seasons on Earth and no climatic zones. The Earth itself supplied the heat felt uniformly over its whole surface. This differs from my conception, as the reader will see presently, in one vital point—as to why the Earth was not heated by the Sun. In the first place Faye’s sun has no _raison d’être_; and in the second no visible means of existence. If its matter were not already within the orbit of the Earth at the time, there seems no reason why it should ever get there; and if there, why it should have been so loath to condense. We cannot admit, I think, any such juvenility in the Sun at the time the Earth was already so far advanced as geology shows it to have been in paleologic times. For the Earth had already cooled below the boiling-point of water. [Illustration: TREE FERN.]