23 8 THE POPULAR SCIENCE MONTHLY. 



planation why this important element has escaped observation by the 

 spectroscope. Additional proof of the existence of oxygen in the outer 

 solar atmosphere has been given by Professor Stoney, the Astronomer 

 Royal for Ireland, and by Mr. R. Meldola in an interesting paper com- 

 municated by him to the "Philosophical Magazine," in June, 1878. 



As regards the sufficiency of an inflowing stream of dissociated 

 vapors to maintain solar energy, the following simple calculation may 

 be of service : Let it be assumed that the stream flowing in upon the 

 polar surfaces of the sun flashes into flame when it has attained the 

 density of our atmosphere, that its velocity at that time is 100 feet per 

 second (the velocity of a strong terrestrial wind), and that in its com- 

 position only one twentieth part is hydrogen and marsh-gas in equal 

 proportions, the other nineteen twentieths being made up of oxygen, 

 nitrogen, and neutral compounds. It is well known that each pound 

 of hydrogen develops in burning about 60,000 heat-units, and each 

 pound of marsh-gas about 24,000 ; the average of the two gases mixed 

 in equal proportion would yield, roughly speaking, 42,000 units ; but, 

 considering that only one twentieth part of the inflowing current is 

 assumed to consist of such combustible matter, the amount of heat 

 developed per pound of inflowing current would be only 2,100 heat- 

 units. One hundred cubic feet, weighing eight pounds, would enter 

 into combustion every second upon each square foot of the polar sur- 

 face, and would yield 8x60x60x2,100 = 60,480,000 heat-units per 

 hour. Assuming that one third of the entire solar surface may be re- 

 garded as polar heat-receiving surface, this would give 20,000,000 heat- 

 units per square foot of solar surface; whereas, according to Herschel's 

 and Pouillet's measurements, only 18,000,000 heat-units per square foot 

 of solar surface are radiated away. There would thus be no difficulty 

 in accounting for the maintenance of solar energy from the supposed 

 source of supply. On the other hand, I wish to guard myself against 

 the assumption that appears to have been made by some critics, that 

 what I have advocated would amount to the counterpart of " perpetual 

 motion," and therefore to an absurdity. The sun can not of course get 

 back any heat radiated by himself which has been turned to a purpose ; 

 thus the solar heat spent upon our earth in effecting vegetation must 

 be absolutely lost to him. 



My paper presented to the Royal Society was accompanied by a 

 diagram of an ideal corona, representing an accumulation of igneous 

 matter upon the solar surfaces, surrounded by disturbed regions 

 pierced by occasional vortices and outbursts of metallic vapors, and 

 culminating in two outward streams projecting from the equatorial 

 surfaces into space through many thousands of miles. The only sup- 

 porting evidence in favor of this diagram were certain indications 

 that may be found in the instructive volume on the sun by Mr. R. A. 

 Proctor. It was therefore a matter of great satisfaction to me to be 

 informed, as I have been by an excellent authority and eye-witness, 



