316 Royal Societij : — 



to superficial conditions. Must not, then, the cause itself be at least 

 partly superficial, and not entirely central ? The author is convinced 

 that such must be the case. He does not profess, in this paper, to 

 carry his speculations further. 



It should be remarked that the argument derived from the above 

 investigations is not directly against the theory of a pi-imitive heat, 

 but only against the manifestation of the remains of such heat as the 

 sole cause of existing terrestrial temperatures in the superficial crust 

 of the globe, at depths beyond the sensible effect of the direct solar 

 heat. Whatever may be the weight of the argument in favour of 

 the earth's original fluidity (and therefore of its primitive heat), 

 founded on the oblateness of its form, for example, the cogency of 

 such argument remains unaltered. At the same time, all the colla- 

 teral arguments in favour of primitive heat, founded on the existing 

 temperature of the earth's crust, or the climatal changes which are 

 believed to have taken place on its surface, are deprived, the 

 author conceives, of nearly all their weight. Moreover, admitting 

 only a part of the existing terrestrial heat to be due to superficial 

 causes, the flow of heat from the earth's central portions must be less 

 by that amount than if the whole flow were due to central heat. 

 Consequently the rate of increase of terrestrial temperature due to 

 the flow of central heat must be proportionally diminished, and the 

 depth at which we should arrive at the temperature of fusion pro- 

 portionally increased. The conclusion, therefore, that the earth's 

 solid crust is as thin as some geologists have supposed it to be, as 

 well as all theories based on that conclusion — whether of volcanic 

 action, or of elevation and depression of the earth's surface — must 

 be deprived of nearly all their force. 



The remainder of this paper contains details of experiments, and 

 descriptions of the apparatus used in making them. 



"On the Perihelia and Nodes of the Planets." By Edward J. 

 Cooper, Esq., F.R.S. 



Early in the year 185.5 I had the honour to transmit to the Eoyal 

 Society a paper on the distribution of the perihelia and ascending 

 nodes of the then discovered planets, which was read at the meeting 

 of the Society held on the 8th of March in that year. In that 

 paper I called attention to my first notice of the phenomena in the 

 Preface to my little work on Cometic Orbits. 



Ten asteroids having been since added to the number, I requested 

 my first assistant, Mr. Graham, to include them in a new distribution 

 of the perihelia and nodes, and he has just reported to me the results. 

 Instead, however, of following precisely the same semicircles which 

 I adopted, be referred in the first instance to the larger planets, with 

 a view to ascertain whether or not in the small planets there were 

 an apparent preference for the heliocentric semicircles in which the 

 perihelia and nodes of the majority of the larger planets are found. 

 Thus,— 



