In the summer of 1840 Agassiz made his first permanent station on the Alps. Hitherto the external phenomena, the relation of the ice to its surroundings, and its influence upon them, had been the chief study. Now the glacier itself was to be the main subject of investigation, and he took with him a variety of instruments for testing temperatures: barometers, thermometers, hygrometers, and psychometers; beside a boring apparatus, by means of which self-registering thermometers might be lowered into the heart of the glacier. To these were added microscopes for the study of such insects and plants as might be found in these ice-bound regions. The Hospice of the Grimsel was selected as his base of supplies, and as guides Jacob Leuthold and Johann Wahren were chosen. Both of these had accompanied Hugi in his ascension of the Finsteraarhorn in 1828, and both were therefore thoroughly familiar with all the dangers of Alpine climbing. The lower Aar glacier was to be the scene of their continuous work, and the centre from which their ascents of the neighboring summits would be made. Here, on the great median moraine, stood a huge boulder of micaceous schist. Its upper surface projected so as to form a roof, and by closing it in on one side with a stone wall, leveling the floor by a judicious arrangement of flat slabs, and rigging a blanket in front to serve as a curtain across the entrance, the whole was presently transformed into a rude hut, where six persons could find sleeping-room. A recess, sheltered by the rock outside, served as kitchen and dining-room; while an empty space under another large boulder was utilized as a cellar for the keeping of provisions. This was the abode so well known afterward as the Hotel des Neuchatelois. Its first occupants were Louis Agassiz, Edouard Desor, Charles Vogt, Francois de Pourtales, Celestin Nicolet, and Henri Coulon. It afforded, perhaps, as good a shelter as they could have found in the old cabin of Hugi, where they had hoped to make their temporary home. In this they were disappointed, for the cabin had crumbled on its last glacial journey. The wreck was lying two hundred feet below the spot where they had seen the walls still standing the year before.