"On this line of reasoning," answered Godfrey, "as the functions of digestion and respiration are connected, the endeavour is to substitute one for the other. Hence the day when chemistry has made the aliments necessary for the food of man capable of assimilation by respiration, the problem will be solved. There is nothing wanted beyond rendering the air nutritious. You will breathe your dinner instead of eating it, that is all!" "Ah! Is it not a pity that this precious discovery is not yet made!" exclaimed the professor. "How cheerfully would I breathe half a dozen sandwiches and a silverside of beef, just to give me an appetite!" And Tartlet plunged into a semi-sensuous reverie, in which he beheld succulent atmospheric dinners, and at them unconsciously opened his mouth and breathed his lungs full, oblivious that he had scarcely the wherewithal to feed upon in the ordinary way. Godfrey roused him from his meditation, and brought him back to the present. He was anxious to proceed to a more complete installation in the interior of Will Tree. The first thing to do was to clean up their future dwelling-place. It was at the outset necessary to bring out several bushels of that vegetable dust which covered the ground and in which they sank almost up to their knees. Two hours' work hardly sufficed to complete this troublesome task, but at length the chamber was clear of the pulverulent bed, which rose in clouds at the slightest movement. The ground was hard and firm, as if floored with joists, the large roots of the sequoia ramifying over its surface. It was uneven but solid. Two corners were selected for the beds and of these several bundles of herbage, thoroughly dried in the sun, were to form the materials. As for other furniture, benches, stools, or tables, it was not impossible to make the most indispensable things, for Godfrey had a capital knife, with its saw and gimlet. The companions would have to keep inside during rough weather, and they could eat and work there. Daylight did not fail them, for it streamed through the opening. Later on, if it became necessary to close this aperture for greater safety, Godfrey could try and pierce one or two embrasures in the bark of the sequoia to serve as windows. As for discovering to what height the opening ran up into the trunk, Godfrey could not do so without a light. All that he could do was to find out with the aid of a pole ten or twelve feet long, held above his head, that he could not touch the top. The question, however, was not an urgent one. It would be solved eventually.