De Luc was born at Geneva, in 1727. His father was a watchmaker, but De Luc’s life was cast on more ambitious lines. He began as a diplomatist, but gravitated insensibly to science. He invented the hygrometer, and was elected a member of the Royal Societies of London, Dublin, and Göttingen. Charlotte, the wife of George III, appointed him her reader; and he died at Windsor, having attained the ripe age of ninety. He was a scientific, rather than a sentimental, mountaineer; his principal occupation was to discover the temperature at which water would boil at various altitudes. His chief claim to notice is that he made the first ascent of the Buet. The Buet is familiar to all who know Chamounix. It rises to the height of 10,291 feet. Its summit is a broad plateau, glacier-capped. Those who have travelled to Italy by the Simplon may, perhaps, recall the broad-topped mountain that seems to block up the western end of the Rhone valley, for the Buet is a conspicuous feature on the line, between Sion and Brigue. It is not a difficult mountain, in the modern sense of the term; but, to climbers who knew little of the nature of snow and glacier, it must have presented quite a formidable appearance. De Luc made several attempts before he was finally successful on September 22, 1770. His description of the view from the summit is a fine piece of writing. Familiarity had not staled the glory of such moments; and men might still write, as they felt, without fear that their readers would be bored by emotions that had lost their novelty. Before leaving, De Luc observed that the party were standing on a cornice. A cornice is a crest of windblown snow overhanging a precipice. As the crest often appears perfectly continuous with the snow on solid foundation, cornices have been responsible for many fatal accidents. De Luc’s party naturally beat a hurried retreat; but “having gathered, by reflection, that the addition of our own weight to this prodigious mass which had supported itself for ages counted for absolutely nothing, and could not possibly break it loose, we laid aside our fears and went back to the terrible terrace.” A little science is a dangerous thing; and it was a mere chance that the first ascent of the Buet is not notorious for a terrible accident. It makes one’s blood run cold to read of the calm contempt with which De Luc treated the cornice. Each member of the party took it in turn to advance to the edge and look over on to the cliff below supported as to his coattails by the rest of the party.