At last, during the period of this great illumination there was thrown a beam of light on the right path for solving this problem. One of the Sidralmo was experimenting on certain substances to see how they behaved under the rays issuing from a lavolan or revealer of inner mechanism. They were chiefly new vegetable substances the properties of which it was his duty to discover and tabulate. He was also mingling one or two new minerals with the plant-products in order to see what modification the blending would cause. One metal had lately been found issuing from the deepest of their lava-wells in the form of vapour; when cooled, it had assumed a crystalline character, and acted to some extent like a magnet; yet it was sensitive to energies that an ordinary magnet ignored, as, for instance, the passage of exceptional nerve-force through the human body. Lightly hung, it quivered when near anyone who happened to be greatly excited. But it paid no heed to the normal currents of energy along the nerves. There was also a species of plant recently evolved that had shown itself singularly sensitive on the approach of any living thing; it shrank not merely from the touch of a hand or of any animal, but from the proximity of life, whilst it remained unmoved when touched by any falling leaf or stone. The experimenter had taken a number of these plants and made of them a basketwork, in which he hung a piece of the new magnetic metal by a slender thread. This he placed above his lavolan to see how the rays from it would affect, or be affected by, the new combination of influences. There seemed to be little or no effect, but he continued his experiment to make sure. Through some imperfection in its walls his vacuum failed; he tried to pump the air out again, but, this failing too, he substituted an alfarene-vacuum which happened to be near him. The result was most striking. The metal, lightly hung in the basket, became agitated at once, and its movements grew more or less active as it approached or was drawn off from the vacuum. After a time it began to show less sensitiveness, and at last became almost quiescent, even though the vacuum remained efficient. On examining the alfarene plant under a magnifier, he found a minute slug, that had evidently escaped the notice of the maker of the vacuum; this had been the source of the agitation of the metal in the basket during its last spasmodic efforts to hold on to life; and, when death, through the lack of air, had overcome it, the agitation had ceased. The plant itself had by the presence of its life kept the test from becoming completely quiescent. The influence of the life of the experimenter himself seemed to be largely neutralised by the surrounding air; it was only when he came very close to the test that it indicated his presence.