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THE POPULAR SCIENCE MONTHLY. 



a law. by which dry land shows itself above 

 the ocean, which he believes to be of al- 

 most universal application to geographical 

 and geological phenomena. The coinci- 

 dences which he describes may be traced by 

 any one on a globe or a large map. The 

 law, as Professor Owen has stated it in a pa- 

 per on the subject presented to the American 

 Association last year, is, in general terms: 

 " The land on our globe shows itself above 

 the ocean-level in definite multiple propor- 

 tions, by measurement; the unit is the an- 

 gular difference between the axis of revolu- 

 tion and the axis of progression. For con- 

 venience, as that angle has been lessening 

 for centuries, we might call it 24. We then 

 have: 



Geographical and geological 

 unit = 24 = z?f- 



Greatest width and length of 

 continents = 3 x 24 = 72 = ^g 



Radius for continents = 36 = ffi 



Half radius " = 18 = 4j 6 j* " 



The measure for oceanic distances is the com- 

 plement of 24 = 06. The ratio of land 

 to water, as shown by Professor Dana, is as 

 100 : 275. The ratio of 24 : 66 : : 100 : 

 275. All measurements are to be estimated 

 at the equator. 



Regarding his law in detail, Professor 

 Owen finds, first, that many longitudinal ele- 

 vations and depressions on the earth's surface 

 (the result apparently of cooling and contrac- 

 tion), especially near the greatest median 

 north and south extension of each conti- 

 nent, coincide with some meridian. This 

 shrinkage has caused a north and south conti- 

 nent to appear in each of the four quarters of 

 the earth, going around on the equator. Mi- 

 nor north and south extensions can be traced 

 at intervals, often of 4i or 9 apart all around 

 the globe, alternating usually with trends 

 which form with them angles of 23i. In 

 verification of this law, adjust the globe so 

 that the poles shall be at the wooden hori- 

 zon and the eastern extremity of Brazil at 

 the brass meridian. Then we shall find the 

 two Americas occupying one, Europe and 

 Africa the second, Asia and Australia the 

 third, and North and South Oceania the 

 fourth, of the quarters into which the rules 

 divide the globe. It will be found that great 

 elevations are matched by depressions on the 

 opposite side of the globe, as the Himalayas 

 and Central Asiatic table-land with Hudson 



Bay, the American lakes, the Gulf of Mex- 

 ico, and the deep southeastern Pacific at 

 180 from them. A second feature is that 

 the outlines of continents form angles of 

 about 23^ with meridians. If we examine 

 the great continental outlines, we shall find 

 in the circuit of the globe five eastern trends 

 of great continents exactly 72, or one fifth 

 of 360, apart. These trends mark belts of 

 seismic force, or lines apparently where the 

 crust has less thickness than under the me- 

 dian lines of continents. The rule of trends 

 may be verified by lifting the north pole of 

 the globe 23| above the, wooden horizon 

 and bringing the continental trends under 

 the brass meridian. Professor Owen finds, 

 third, that besides these two forces which 

 exert their powers along lines parallel, re- 

 spectively, to the axis of revolution and to 

 that of progression, each continent has two 

 foci nearly on its median line, concentric 

 circles around which mark important addi- 

 tions to the land and orography of the con- 

 tinent, and pass, as they successively en- 

 large, through areas of consecutive geolog- 

 ical periods from the older to the newer. 

 One of the feci, and the dominant one in 

 the northern continents, is near the Arctic 

 Circle ; the other is in the geographical cen- 

 ter of the continent. The southern conti- 

 nents have only the latter. The foci for 

 North America are in Boothia Felix, near 

 longitude 96 west, and latitude 71 north, 

 and near the height west of Lake Superior, 

 longitude 94 west, and latitude 48 north. 

 A radius of 24 from the northern focus 

 reaches the southern limits of the archaean 

 area near Lake Superior and its junc. 

 tion with the palaeozoic ; and one of 29 

 or 30 takes in the mesozoic of Kansas 

 and the new red sandstone of Connect- 

 icut and Massachusetts, with a valley of 

 erosion between. Drawing our circles from 

 the west shore of Lake Superior, a radius 

 of 11 or 12 gives us Silurian, lower and 

 upper, from Niagara to near Springfield, 

 Ohio, Lexington and Frankfort, Kentucky, 

 and Nashville, Tennessee, dominating at 

 least the eastern half of the circle, while 

 the western part was still under water. A 

 radius of 12 to 13 marks the Appalachian 

 and other coal-fields; and of 15, the meso- 

 zoic formation curving from the cretaceous 

 of Utah and Colorado through the interme- 



