The following is the result of some numerical statements, the comparison of which affords more precise ideas on the structure of mountains in general.* (* The Cols or passes indicate the minimum of the height to which the ridge of the mountains lowers in a particular country. Now, looking at the principal passes of the Alps of Switzerland (Col Terret, 1191 toises, Mont Cenis, 1060 toises; Great Saint Bernard, 1246 toises; Simplon, 1029 toises; and on the neck of the Pyrenees, Benasque, 1231 toises; Pinede, 1291 toises; Gavarnic, 1197 toises; Cavarere, 1151 toises; it would be difficult to affirm that the Pyrenees are lower than the average height of the Swiss Alps.) TABLE OF HEIGHTS OF VARIOUS RANGES. COLUMN 1 : NAMES OF THE CHAINS OF MOUNTAINS. COLUMN 2 : THE HIGHEST SUMMITS IN TOISES. COLUMN 3 : MEAN HEIGHT OF THE RIDGE IN TOISES. COLUMN 4 : PROPORTION OF THE MEAN HEIGHT OF THE RIDGES TO THAT A THE HIGHEST SUMMITS. Himalayas (between north latitude : 4026 : 2450 : 1 : 1.6. 30 degrees 18 minutes and 31 degrees 53 minutes, and longitude 75 degrees 23 minutes and 77 degrees 38 minutes) Cordillera of the Andes (between : 3350 : 1850 : 1 : 1.8. latitude 5 and 2 degrees south) Alps of Switzerland : 2450 : 1150 : 1 : 2.1. Pyrenees : 1787 : 1150 : 1 : 1.5. Littoral Chain of Venezuela : 1350 : 750 : 1 : 1.8. Group of the Mountains of the Parime : 1300 : 500 : 1 : 2.6. Group of the Mountains of Brazil : 900 : 500 : 1 : 2.3. If we distinguish among the mountains those which rise sporadically, and form small insulated systems,* (* As the groups of the Canaries, the Azores, the Sandwich Islands, the Monts-Dores, and the Euganean mountains.) and those that make part of a continued chain,* (* The Himalayas, the Alps, and the Andes.) we find that, notwithstanding the immense height* of the summits of some insulated systems (* Among the insulated systems, or sporadic mountains, Mowna-Roa is generally regarded as the most elevated summit of the Sandwich Islands. Its height is computed at 2500 toises, and yet at some seasons it is entirely free from snow. An exact measure of this summit, situated in very frequented latitudes, has for 25 years been desired in vain by naturalists and geologists.), the culminant points of the whole globe belong to continuous chains--to the Cordilleras of Central Asia and South America.