Many theories have been put forward to explain what the corona really is; some saying that it is cometary matter, others that it is merely nebulous; that it is formed of streams of myriads of meteorites; that it is merely a form of Zodiacal Light, and again others that it is nothing more than the glare of the furnace below reflected on the upper strata of atmosphere, as that of a terrestrial furnace is reflected on the clouds above it. It was, therefore, a proud moment when, after long investigation, the explorers could settle all these points of doubt, and prove it to be gaseous, finding, at various portions of its mass, oxygen, combining in enormous quantities with hydrogen, carbon, phosphorus, carbon mon-oxide, and sulphur, the combustion being accompanied with terrific heat and noise. Some idea of the amazing heat may be gathered from the fact that there were thousands of miles of carbon existing in combination with other of the most refractory elements as extremely thin and tenuous vapour, accompanying which were violent electric discharges, which encircled the _Regina_ hour after hour and day after day in a tireless surging sea which, until the first fear had subsided, had paled the faces of the occupants, for the flood was so incessant that they could not help doubting if their protecting force would be proof against it, so close it seemed as they gathered round the windows trying to believe they were safe, longing for it either to terminate or for the annihilating stroke to end their suspense and close the terrible waiting for the death that tarried. But as it was perceived that although the _Regina_ was the focus of all the wild, electric fluid of the zones and strata through which she sank, she continued her roving course unfettered and unharmed as if in a shower of Earth-rain, all fear gradually subsided, and the voyagers could look on the awful scene as on a wondrous panorama; with no alarm and scarcely an expression of surprise except when some more than usually magnificent effect compelled their voiced admiration. And all this time as the ship was sinking with a slow and steady descent, the clouds were dropping their elements, cooled from their gaseous state to finely powdered dust, to be reheated and blown back in fresh clouds of white and glowing gas, which mounted higher and higher in an endless repetition.