The sun and heaven were glorious, but the cold was nevertheless intense, for it had frozen bitterly the night before. The mountain seemed more noble and lovely than when I had last ascended it; and as I climbed the slopes, crossed the shining cols, and rounded the vast snow-bosses of the mountain, the sense of being alone lent a new interest to the glorious scene. I followed the track of those who preceded me, which was that pursued by Lauener and myself a week previously. Once I deviated from it to obtain a glimpse of Italy over the saddle which stretches from Monte Rosa to the Lyskamm. Deep below me was the valley, with its huge and dislocated _neve_, and the slope on which I hung was just sufficiently steep to keep the attention aroused without creating anxiety. I prefer such a slope to one on which the thought of danger cannot be entertained. I become more weary upon a dead level, or in walking up such a valley as that which stretches between Visp and Zermatt, than on a steep mountain side. The sense of weariness is often no index to the expenditure of muscular force: the muscles may be charged with force, and, if the nervous excitant be feeble, the strength lies dormant, and we are tired without exertion. But the thought of peril keeps the mind awake, and spurs the muscles into action; they move with alacrity and freedom, and the time passes swiftly and pleasantly. [Sidenote: LEFT ALONE. 1858.] Occupied with my own thoughts as I ascended, I sometimes unconsciously went too quickly, and felt the effects of the exertion. I then slackened my pace, allowing each limb an instant of repose as I drew it out of the snow, and found that in this way walking became rest. This is an illustration of the principle which runs throughout nature--to accomplish physical changes, _time_ is necessary. Different positions of the limb require different molecular arrangements; and to pass from one to the other requires time. By lifting the leg slowly and allowing it to fall forward by its own gravity, a man may get on steadily for several hours, while a very slight addition to this pace may speedily exhaust him. Of course the normal pace differs in different persons, but in all the power of endurance may be vastly augmented by the prudent outlay of muscular force.