It is reckoned that about 20 glacier passes were certainly known before 1600, about 25 more before 1700, and yet another score before 1800; but though the attempt of P.A. Arnod (an official of the duchy of Aosta) in 1689 to "re-open" the Col du Ceant may be counted as made by a non-native, we do not come upon another case of the kind till the last quarter of the 18th century. Nor did it fare much better with the high peaks, though the two earliest recorded ascents were due to non-natives, that of the Rochemelon in 1358 having been undertaken in fulfilment of a vow, and that of the Mont Aiguihe in 1492 by order of Charles VIII of France, in order to destroy its immense reputation for inaccessibility -- in 1555 Conrad Gesner did not climb Pilatus proper, but only the grassy mound of the Gnepfstein, the lowest and the most westerly of the seven summits. The two first men who really systematically explored the regions of ice and snow were H.B. de Saussure (1740-1799), as regards the Pennine Alps, and the Benedictine monk of Disentis, Placidus a Spescha (1752-1833, most of whose ascents were made before 1806), in the valleys at the sources of the Rhine. In the early 19th century the Meyer family of Aarau conquered in person the Jungfrau (1811) and by deputy the Finsteraarhorn (1812), besides opening several glacier passes, their energy being entirely confined to the Bernese Oberland. Their pioneer work was continued in that district, as well as others, by a number of Swiss, pre-eminent among whom were Gottlieb Studer (1804-1890) of Bern, and Edouard Desor (1811-1882) of Neuchatel. The first-known English climber in the Alps was Colonel Mark Beaufoy (1764-1827), who in 1787 made an ascent (the fourth) of Mont Blanc, a mountain to which his fellow-countrymen long exclusively devoted themselves, with a few noteworthy exceptions, such as Principal J.D. Forbes (1809-1868), A.T. Malkin (1803-1888), John Ball (1818-1889), and Sir Alfred Wills (b. 1828). Around Monte Rosa the Vincent family, Josef Zumstein (1783-1861), and Giovanni Gnifetti (1801-1867) did good work during the half century between 1778 and 1842, while in the Eastern Alps the Archduke John (1782-1850), Prince F.J.C. von Schwarzenberg, archbishop of Salzburg (1809-1885), Valentine Stanig (1774-1847), Adolf Schaubach (1800-1850), above all, P.J. Thurwieser (1789-1865), deserve to be recalled as pioneers in the first half of the 19th century. In the early fifties of the 19th century the taste for mountaineering 1apidly developed for several very different reasons. A great stimulus was given to it by the foundation of the various Alpine clubs, each of which drew together the climbers who dwelt in the same country. The first was the English Alpine Club (founded in the winter of 1857-1858), followed in 1862 by the Austrian Alpine Club (which in 1873 was fused, under the name of the German and Austrian Alpine Club, with the German Alpine Club, founded in 1869), in 1863 by the Italian and Swiss Alpine Clubs, and in 1874 by the French Alpine Club, not to mention numerous minor societies of more local character. It was by the members of these clubs (and a few others) that the minute exploration (now all but complete) of the High Alps was carried out, while much has been done in the way of building club huts, organizing and training guides, &c., to smooth the way for later comers, who benefit too by the detailed information published in the periodicals (the first dates from 1863 only) issued by these clubs. Limits of space forbid us to trace out in detail the history of the exploration of the High Alps, but the two sub-joined lists give the dates of the conquest of about fifty of the greater peaks (apart from the two climbed in 1358 and in 1402, see above), achieved before and after 1st January 1858. As a proof of the rapidly-growing activity of Englishmen, it may be pointed out that while before 1858 only four summits (the Mittelhorn, or central peak of the Wetterhorner, the highest point of Monte Rosa, Laquinhorn and Pelmo) were first ascended by Englishmen, in the case of the second list only five (Grand Combin, Wildspitze, Marmolata, Langkofel and Meije) were not so conquered (if the present writer, an American, be included among the English pro hac vice.)