“It is more than that,” was the reply; “it means that there is ‘sound’ outside.” “Really!” remarked Godfrey, banteringly. “Surely we have had enough sound outside since we came near the sun to make a little more or less now a matter of no surprise—but you physicists have always something wonderful up your sleeve, haven’t you, Gilbert? What is it now?” All the rest laughed at Godfrey’s manner, and Gilbert, turning to his chum, retorted, laughingly,—“This will prove a lesson in deduction, old man, and show you how to make one fact elucidate another!” And then more seriously,—“You notice that after passing through the enormously thick sun-crust we came to silence; all the upper thundering noises were cut off. We entered a stratum of nitrogen which even the sun could not burn; then a little lower and it became mixed with oxygen; now the percentage of oxygen is higher. So far, everything points, as you all know, to the presence far below us of a breathable atmosphere—breathable to us, I mean—and we are all naturally asking ourselves the question, ‘Why this breathable air if there is no need for it?’ and the presence of ‘sound,’ faint as it is, strengthens the supposition. _If_ there is sound, as there is, something must make it, and given an atmosphere capable of supporting human life, added to sound, or the echo of sound as we might call it, which is now absent as we are all moving, it is highly probable that something living exists below. If you will kindly turn the ship on its axis, Ross, so as to alter the direction of our waves to run parallel to those outside, we shall find, unless I am very much mistaken, a modification of the same law, and the two sounds which seem now to have changed and to run in unison will be doubled when they run side by side.” This was proved to be the case, and a sound coming from the instrument, though faint, was distinctly audible, and the vibrations were numbered on the dial. “It is possible that down below us we shall find light, of course,” remarked Parkin Coombes. “More than possible,” replied Rowland. “What new phase has turned up now? Do you mean to say we are likely to be lit up shortly?” interposed Godfrey.