A NEW THEORY OF THE SUN. 237 



more intricate phenomena of solar physics, I have long had a convic- 

 tion, derived principally from familiarity with some of the terrestrial 

 effects of heat, that the prodigious dissipation of solar heat is unneces- 

 sary to satisfy accepted principles regarding the conservation of en- 

 ergy, but that solar heat may be arrested and returned over and over 

 ao-ain to the sun, in a manner somewhat analogous to the action of the 

 heat recuperator in the regenerative engine and gas-furnace. The 

 fundamental conditions are : 



1. That aqueous vapor and carbon compounds are present in stellar 

 or interplanetary space. 



2. That these gaseous compounds are capable of being dissociated 

 by radiant solar energy while in a state of extreme attenuation. 



3. That the vapors so dissociated are drawn toward the sun in 

 consequence of solar rotation, are flashed into flame in the photo- 

 sphere, and rendered back into space in the condition of products of 

 combustion. 



Three weeks have now elapsed since I ventured to submit these 

 propositions to the Royal Society for scientific criticism, and it will 

 probably interest my readers to know what has been the nature of 

 that criticism and the weight of additional evidence for or against my 

 theory. 



Criticism has been pronounced by mathematicians and physicists, 

 but affecting singularly enough the chemical and not the mathemat- 

 ical portion of my argument ; whereas chemists have expressed doubts 

 regarding my mathematics while accepting the chemistry involved in 

 my reasoning. 



Doubts have been expressed as to the sufficiency of the proof that 

 dissociation of attenuated aqueous vapor and carbonic acid is really 

 effected by radiant solar energy, and, if so effected, whether the 

 amount of heat so supplied to the sun could be at all adequate in 

 amount to keep up the known rate of radiation. It was admitted in 

 my paper that my own experiments on the dissociation of vapors 

 within vacuous tubes amounted to inferential rather than absolute 

 proof ; but the amount of inferential evidence in favor of my views 

 has been very much strengthened since by chemical evidence received 

 from various sources ; and I will here only refer to one of these. 



Professor Piazzi Smyth, the Astronomer Royal for Scotland, has, 

 in connection with Professor Herschel, of Newcastle, recently pre- 

 sented an elaborate paper or series of papers to the Royal Society of 

 Edinburgh "On the Gaseous Spectra in Vacuum-Tubes," of which he 

 has kindly forwarded me a copy. It appears from these memoirs that 

 when vacuum-tubes, which contain attenuated vapors, have been laid 

 aside for a length of time, they turn practically into hydrogen-tubes. 

 In another very recent paper presented to the Royal Society of Edin- 

 burgh, Professor Piazzi Smyth furnishes important additional proof of 

 the presence of oxygen in the outer solar atmosphere, and gives an ex- 



