4 z THE POPULAR SCIENCE MONTHLY. 



including the discovery of the long-sought northwestern passage, and 

 of its inutility. The exploration of the antarctic circle as far as the 

 73 of south latitude, and the remarkable discovery that the ice-bound 

 regions, both of the Arctic and Antarctic, were, at a former period of the 

 world's history, covered with a luxuriant vegetation, and that plants 

 and animals then existed there in great abundance, which are found 

 now only in the tropics, or in the more southern parts of the temperate 

 zone. 



And finally our own explorations of the great Western region, 

 between the Mississippi and the Pacific, by Fremont, Emory, Simpson, 

 Marcy, Stansbury, Sitgreaves, Gunnison, Beckwith, Whipple, Wil- 

 liamson, Parke, Warren, Ives, Reynolds, Macomb, Mullen, Wheeler, 

 and other gallant, efficient, and distinguished military officers con- 

 ducting reconnoissances or expeditions across its plains, deserts, and 

 mountains, accompanied in these expeditions by scientific civilians, to 

 whose labors we are indebted for our knowledge of its geology, agri- 

 cultural resources, and natural history. Among strictly scientific 

 works by civilians I should also enumerate Whitney's survey of Cali- 

 fornia, followed by King and Gardner's belt of geological and topo- 

 graphical survey across the North American Cordilleras, Hayden and 

 Gardner's survey in the Rocky Mountains, and Powell and Thompson's 

 of the great canons of the Colorado, through whose united labors so 

 much of the geography of this vast region has become known ; its 

 great mountain-ranges, extraordinary canons, wonderful geysers, deep- 

 ly interesting ruins of a prehistoric and semi-civilized people of whom 

 we know but little ; its lakes, rivers, majestic cataracts, broad areas 

 of cultivable land, already largely and to be still more extensively 

 settled, and finally the millions it has yielded in gold and silver ; a 

 region so vast beyond the one hundredth meridian, that it will be 

 twenty years before we obtain proper maps of it, unless the Govern- 

 ment is more liberal in providing for its exploration and survey than 

 it has hitherto been. 



To these geographical labors and explorations within this period 

 in various parts of the globe must also be added extensive researches 

 of a geographical character, such as deep-sea dredgings, for the inves- 

 tigation of the temperature of the ocean, the movements of submerged 

 currents, the plant and animal life existing at great depths, and the 

 configuration of the bottom of the seas. The observation and study 

 of oceanic currents and their cause. The distribution of heat north 

 and south of the equator by the instrumentality of these currents, and 

 its efl'ects upon climate, as well as the effect of the currents from polar 

 regions in modifying the heat of the equator. The meteorological ob- 

 servations in respect to the course of the winds; and the investiga- 

 tions of the laws and of the cause of hurricanes, cyclones, and other 

 aerial disturbances. The magnetic observations in elucidation of the 

 difficult subject of terrestrial magnetism. The numerous measure- 



