National Geographic : 1894 Jan 31
120 G. G. Hubbard-Air and Water, Temperature and Life. regions are basins, where the rivers and rainfall either run into salt lakes or are lost in the desert and never reach the ocean. These deserts are caused by the winds which blow either from colder over warm areas and are therefore dry, or over vast plains or mountainous regions upon which they nave precipitated their moisture. The average rainfall on the great deserts does not exceed ten inches a year, and the evaporation is usually greater than the rainfall. They are situated generally between the twentieth and fortieth degrees of north latitude and between the twen tieth and thirtieth degrees of south latitude. In the northern belt are the Carson and other basins of Nevada, the Salt Lake of Utah, the desert of Sahara, Arabia, Persia, the Aral-Caspian desert, the Tanin Gobi and Mongolia desert. In the southern belt is the desert of Atacama in South America, Kalahari in South Africa and the Australian deserts. These basins in the northern belt contained formerly, lakes much greater than are now found in either of the continents. Salt Lake was formerly much larger and deeper, for its waters once beat upon shores one thousand feet higher up the moun tain sides than at present; its waters then found their way to the ocean. This was probably in the ice age, when the surround ing mountains were covered with snow and great glaciers, and the evaporation was much less than the rainfall and the water from the melting glaciers. In the desert of Sahara numerous dry water-courses show where great rivers formerly ran into Lake Tchad. In Asia the Caspian and Aral seas were connected, covering a territory many times greater than at present, with an outlet to the Bosphorus and Mediterranean. We have not sufficient knowledge of Arabia to know the former condition of that arid country. The process of desiccation is still going on, and how much longer it will continue no one can tell. Mountains of America. Next we will notice the influence of the mountains on the atmosphere, either in enriching or impoverishing a country, or in intensifying the movements of the currents of air and water. The mountains of America rise at the Arctic ocean and form the divide between the Mackenzie and Yukon rivers. A second range runs from northeastern Alaska through Mount Saint Elias.
1894 Feb 14
1893 Jul 10