454 J. LEWIS DIMAN, D.D. 



meteoric constitution of the universe. Especially in October, 1879, he 

 gave a series of eight proi^osilions in Cosmical Physics. At an in- 

 formal scientific meeting at Harvard University he stated five others, 

 which have been since printed in the Appendix to his " Lectures on 

 Ideality in Science." They were given rather as a basis for criticism 

 and discussion than as fully proved. They are founded upon the 

 theory of Mayer, which is advocat^ed by Sir William Thomson, that 

 solar heat, and in part planetary heat, are supplied by the collision of 

 meteors with the sun and planets. Small portions of matter in space 

 cool and become invisible solid meteors. These, by their impact with 

 the sun, produce the violent commotions of the sun's surface. A por- 

 tion of the earth's heat comes from the sun, another portion directly 

 from the impact of meteors with the earth's atmosphere. The two 

 portions, he afterwards shows, are equal. 



These views are developed more fully in his " Lectures," recently 

 published. The meteors, as Professor Peirce believed, come from the 

 outer portions of the condensing solar nebula. In the course of devel- 

 opment an outer shell was left, which furnished the matter to be col- 

 lected, in small masses. The smallest become meteors, the larger 

 comets. Their numbers are enoi-mously great. Arranged according 

 to perihelion distances, the number of comets or meteors coming within 

 a given distance of the sun varies directly as the distance. The heat 

 of Jupiter and Saturn comes from the collisions with those planets. 

 The interior of the earth may be liquid throughout, and the limits set 

 to the lengths of the geologic ages may reasonably be greatly extended. 



Any attempt to outline the history of the solar system is sure to 

 lead, in the present state of knowledge, into serious dithculties. Some 

 of the positions assumed by Professor Peirce, especially Mayer's 

 theory of the source of the sun's heat, will be contested. Even if some 

 portions are not found true, the parts would not all fall together, and 

 we may well leave them all to the discussion that he invited for 

 them. 



ASSOCIATE FELLOWS. 



J. LEWIS DLM.VN, D.D. 



J. Lewis Diman, D.D. was born at Bristol, Rhode Island, May 

 1, 1831. lie was prepared for college in his native place, and grad- 

 uated at Brown University in 1851. He subsequently spent sev- 



