The theory proved so far correct that next day the upright was down, but the wire had snapped and the rabbit was gone. The character of the fracture clearly indicated how it had happened: the rabbit, so soon as he found his head in the noose, had rolled and tumbled till the wire, already twisted tight, parted. Too much twisting, therefore, weakened instead of strengthening. Next a single wire, somewhat thicker, was used, and set up nearly in the same place; but it broke again. Finally, two strands of medium size, placed side by side, but only twisted once—that is, just enough to keep them together—were employed. The lesser loop—the slip-knot, as it might be called—was at the same time eased in order to run quicker and take a closer grip. Experiments with the hand proved that this style of wire would bear a great strain, and immediately answered to a sudden jerk. The running noose slipped the more easily because the wires were smooth; when twisted the strands checked the noose, the friction causing a slight sound. The wire itself seemed nearly perfect; but still no rabbit was caught. Various runs were tried in succession; the size of the loop, too, was now enlarged and now decreased; for once it seemed as if a rabbit’s ears had struck it aside, and on another as if, the loop being too large or too low down, one of the fore feet had entered and drawn it. Had it been the hind leg the noose would have held, because of the crook of the leg; but the fore foot came through, leaving the noose drawn up to a size not much larger than a finger-ring. To decide the point accurately, a full-grown rabbit was shot, and Orion held it in a position as near as possible to that taken in running, while I adjusted the wire to fit exactly. Still no success. At last the secret was revealed by a hare. One day, walking up the lane with the gun, and peeping over into the ploughed field, I saw a hare about sixty yards away. The distance was too great to risk a shot, or rather it was preferable to wait for the chance of his coming nearer. Stepping back gently behind the bushes, I watched him run to and fro, gradually approaching in a zig-zag line that must carry him right across in front. I was positive that he had not seen me, and felt sure of bagging him; when suddenly—without any apparent cause—up went his head, he glanced round, and was off like the wind. Yet there had not been the faintest noise, and I could not understand it, till all at once it occurred to me that it must be the scent. The slight, scarcely perceptible, breeze blew in that direction: instantly he crossed the current from me he detected it and fled. Afterwards I noticed that in the dusky twilight, if the wind is behind him, a hare will run straight at you as if about to deliberately charge your legs. This incident by the ploughed field explained the failure of the wire. Every other care had been taken, but we had forgotten to allow for the extreme delicacy of a wild animal’s sense of smell.