them part of the provisions, they were sent with the baggage to wait at the place where they had encamped the night before. This circumstance very much discouraged the travellers. Being left without instruments they had to relinquish the physical and astronomical observations which they had proposed to make, and thereby missed the principal object of their journey. They nevertheless determined to persevere, for the purpose of examining well the situation, and noting such points as might facilitate any subsequent attempt undertaken with better preparations. Soon after this the clouds dispersed, and they reached a passage which was very steep and covered with loose stones, and through which they ascended with much labor, extending their line so as to prevent the stones rolling on those below. The fatigue and the pain in their knees, obliged them to rest every eight or ten paces. After an hour's travelling in this manner they reached a body of basaltic rock, which being very steep they could not surmount but with great difficulty, and only by leaping from one rock to the other, at great risk. After this they got into a bed of loose sand, (apparently pumice stone reduced to dust,) and ascended to a very high rock, which from Mexico appears like a speck. The rock is a great mass of compact black basalt forming some imperfect pillars, the fissures being filled with solid ice. They observed from time to time small stones falling upon them, as if thrown from above, and began to experience headache and nausea, which affected Quintana more than the others. The barometrical observation here showed an elevation of 16,895 English feet above the ocean. After taking some slight refreshments, and resting about an hour, they continued their ascent. It is impossible to detail the particulars of the frequent difficulties and risks encountered until the explorers reached the sandy acclivity which forms the dome of the mountain, and the firmness with which they overcame them. At this point they took another short rest--fancying themselves very near the end of their labors, and deceived by the great rarefaction of the air, which made objects appear much nearer than they really were, they forgot what they had already undergone, and Mr. Glennie was entirely taken up with the prospect of soon putting his barometer in operation on the very summit. At this time Quintana who had smoked a good deal and was otherwise much fatigued, complained of excessive headache and fell down exhausted. They concluded that at these great elevations smoking is as impracticable as the use of ardent spirits. The servant was vainly encouraged to proceed, and finding it impossible, they directed him to await their return where he was.