Nor are we to think it strange, if after so great a quantity of luminous vapour had been carried up into the ether, out of the pores of the earty, the cause of its effervescence at length abating, or perhaps the matter consumed, these effluvia should at length subside, and form those two bright luminations which we have described; and, whose edges being turned to us, were capable to emit so much light that we might rea by them. I choose to call them luminations, because, though they were but thin, doubtless they spread horizontally over a large tract of the earth's surface.