400 



THE POPULAR SCIENCE MONTHLY. 



Scale, 75,000 miles to the inch. 



Fig. 18. 



Fig. 21. 



Prominence as it appeared at half-past 

 twelve o'clock, september 7, 1871. 



Fig. 22. 



Vertical Filaments. 



as the above appeared hale an hour later, 

 when the uprushing htdrogen attained a 

 Height of more than 200,000 Miles. 



Fig. 23. 



Flames. 



Spot near the Sitn's Limb, with accompanying 

 Jets of Htdrogen, as seen October 5, 1871. 



each minute a shell of ice nearly forty feet thick over his entire surface) 

 would require the condensation of enough vapor to make a sheet of 

 liquid five feet thick in the same time— supposing, that is, the latent 

 heat of the solar vapors not greater than that of water vapors. This, 

 of course, is uncertain, but, so far as we know, very few if any vapors 

 contain more latent heat than that of water, and we may therefore 

 consider it roughly correct to estimate the continuous production of 



