Away up in the high valleys formed among the peaks of the tallest mountain ranges of both the Rocky Mountains and the mountains of Alaska, as well as those in Switzerland and European countries, the snow freezes into great solid masses because of the intense cold, and is forced by its own pressure into vast fields and mountains of ice. This ice is not like that produced by the freezing of water, but resembles more a very hard, solid form of snow, being composed of thin layers filled with air bubbles and more brittle and less transparent than the ice we are accustomed to see. Glaciers exist in all zones in which mountains rise above the snow-line, that is, the height where it is so cold that there is always snow. We all know that if we press two pieces of ordinary ice together each piece will melt at the place where it touches the other and just in that same way the pressure of the ice above them causes glaciers to be continually moving downward, frequently reaching the borders of cultivation even. As they descend they also experience a gradual diminution from the action of the sun and rain, and from the heat of the earth. Investigation has shown that they move very much like a river, the middle and upper parts faster than the sides and bottom, similar to the way in which a mass of thick mortar or a quantity of pitch flows down an inclined trough. The rate at which a glacier moves generally varies from eighteen to twenty-four inches in a day. The Glacier National Park is the latest addition to the series of great natural attractions which the United States Government has been acquiring for years. It lies in Northern Montana, between the Canadian border and the line of the Great Northern Railroad, and contains about a million acres of natural wonders, ranging from verdant valleys and wooded heights to glacial peaks. There are numerous glaciers and mountain lakes and the locality presents many examples of sublime scenery. The City of Tacoma, Washington, is situated in the valley below Mt. Rainier and commands a wonderful view of that mountain, on which there is situated one of the largest glacial systems in the world radiating from any single peak. One of the most famous glaciers of the Alps is the Mer de Glace, belonging to Mont Blanc, in the valley of Chamouni, about fifty-seven hundred feet above the level of the sea. Those of the Andes and the Southern Alps of New Zealand are conspicuous, and they abound in Norway, Iceland and Spitzbergen, but it is more especially in the chain of Monte Rosa that the phenomena of glaciers are exhibited in their greatest wonder, as also in their most interesting phases from a scientific point of view. How Large are Molecules?