TLANETESIMAL THEORIES OF THE EARTH'S ORIGIN. 211 



with evolutionary law. This formed the fundamental idea of my 

 graduation thesis for the Doctorate in Science, which was submitted 

 to the University of London in 1888, and was published with 

 considerable additions by Messrs. Longmans and Co., in 1889, under 

 the title of Chemical and Physical Studies in the Metamorphism of 

 Rocks. The conception, which I was thus able to form of the 

 evolution of this globe, would seem therefore to have anticipated, 

 by a decade or more, a good deal that Mr. Upham has brought 

 forward in the latter part of his paper. I have returned to this 

 subject of late, and have already in MS. a little work nearly ready 

 for the press, in which stress is laid upon the confirmation given to 

 my published views by the "spiral nebulae" during the last three 

 or four years. This flashed upon my mind, when I had the great 

 pleasure of listening to Sir Robert Ball's splendid address to the 

 Victoria Institute in 1903, and of seeing the photographs which on 

 that occasion he threw upon the screen. 



In the work, whose title is given above, will be found a discursus 

 (pp. 22-24) on the results that would follow from the assumption of 

 the following laws and principles : — 



1. The law of universal attraction, and the specialised 



operation of this law in all cases of gravitation. 



2. Elevation of temperature, when latent heat is set free either 



in the liquefaction of aeriform matter or in the solidifica- 

 tion of liquids. 



3. Transformation of potential energy due to chemical affinity 



into heat in chemical combination. 



4. Dissipation of energy, as it is transformed into heat. 



5. Transformation of energy into heat in all cases of impact. 



6. Retardation of radiation by non-diathermanous gases and 



vapours. 



7. The enormous range of condensation-temperatures of the 



known chemical elements from that of platinum, osmium 

 or rutheniun to that of hydrogen gas. 



In the second appendix to the above work there appears also a 

 discursus on the moon's surface, as throwing light upon the 

 conditions of our planet in the pre-oceanic stage of its develop- 

 ment. 



This has also been discussed more recently bv Professor Suess of 



