“Yes, indeed it is,” answered Rowland. “This soup-like appearance is due entirely to fine particles of metallic and other dust which, when taken away, leaves absolutely pure nitrogen.” “Then the inference is obvious!” cried Rutherford and several others. “Assuredly,” agreed Gilbert; “all is now clear as daylight. We have passed through the immensely thick crust of the sun, and either come into a stratum of nitrogen or the whole interior of the planet is nitrogen.” Here, indeed, was a discovery. This gas, nitrogen, from its being neutral and neither inflammable nor a supporter of combustion, either had put out the solar fire or caused a thick black crust of solid matter to form, which was the black portion through which they had recently passed, and the fine particles of solidified sun-dust were falling towards the centre, drawn thither by their own gravity; those being eliminated, nitrogen only remained. “All has come to pass as you foretold, Oakland,” said Parkin Coombes; “but in spite of the _Regina’s_ powers it seems a marvellous thing that the sea has not rushed in after us, through the aperture we made.” “And if the atoms were pushed aside by the _Regina_ and pressed into the parts adjacent, so as to allow free passage to the ship, one would think the sides of the well-like opening we made would become so tightly packed as to prevent the re-formation of the atoms in their original position, and thus form a shaft down which the sea could pour,” said Farrant. “Yes,” replied Dennis, “that is what would occur ordinarily; but being temporarily turned into vapour by our de-atomising force, the atoms would, almost instantly after our passage, resume their former condition, and what heat had been imparted to them by the change would be destroyed by this nitrogen. Consequently, we have not disturbed the crust—actually—although, considering the circumstances, how we have escaped being involved in an awful explosion is a mystery.” “Anyway, it is evident we _are_ fairly inside Dan Phœbus!” exclaimed Rowland; “and whether we caused an extra explosion up above or not is immaterial, for it is certain that the crust is as substantial as before, or the fiery sea even now would be pouring down on us and into the interior.” Their discovery of the nitrogen could not do otherwise than cause a violent sensation, and every one buttonholed his neighbour, and talked and expounded theories galore. Then Gilbert asked them to come into the laboratory, and they trooped in _en masse_, for each knew what such a revelation meant, and to what it might lead, and every one was on the tip-toe of expectancy. Fresh samples were taken, with the same result as before; they were in a sea of nitrogen, safe from fire—but were they safe from chemical action?