No doubt the desire to ascend into the air always possessed man, but owing to the awe with which mountains seem to have inspired the ancients, there is rarely mention in their writings of climbing mountains, or of the physiological effects which could hardly have failed to be apparent upon high summits. Citing one of the few existing narratives, Aristotle relates: "Those which ascend to the top of the mountain Olympus could not keep themselves alive without carrying with them wet sponges, by whose assistance they could respire in that air otherwise too thin for respiration." This mountain of less than 10,000 feet was said to be so high that it never rained on its summit, where, it was supposed, the air was always still. A still higher mountain, easily accessible to the ancient world, and which we know was ascended, is Etna. Concerning the progress of meteorology, from the time of the ancient Romans to the revival of knowledge in Europe, there is little to say except that during the middle ages meteorology, like other learning, was confined to the monasteries. Speculations were current as to the extent of the atmosphere until, in the middle of the eleventh century, Alhazen, a learned Arab, computed from the duration of twilight that the atmosphere extended nineteen leagues above the earth. The same method was applied with more precision by Tycho Brahe, Kepler, and other astronomers of the sixteenth and seventeenth centuries. The earliest weather chronicles were probably noted by monks from time to time in almanacks or missals, although when this was done first we do not know. The oldest daily chronicles of the weather extant are those kept by William Merle in Oxford from 1337 to 1344. We owe it to the late Mr. Symons, the English meteorologist and bibliophile, that this MS. and many other old records have been brought to light and published. Dr. Hellmann has done even more in Germany, and this historical research is evidence of the growing importance of the science of meteorology.