Page:Popular Science Monthly Volume 4.djvu/416

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Scale, 75,000 miles to the inch
PSM V04 D416 Quiescent prominences.jpg

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 timeā€”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