SCIENCE. 



227 



per, not so much in older rocks as in later formations. 

 Demonstration : 



I. PARAMAGNETIC METALS AND THEIR ORES. 



i. Iron. — A considerable portion of this metal as 

 magnetite, both in the United States and in Scandi- 

 navia, is magnetic, possessing polarity. Specimens 

 from Magnet Core, Ark., and from near Pilot Knob, 

 Missouri, in the United States, and from Dannemora, 

 in Sweden, present this character very strongly. 



(a) Nearly all the important iron of the United 

 States (as can be ascertained from Dana's Mineralogy, 

 or readily seen by inspecting Map No. VIII in Cor- 

 nell's Phys. Geogr.) occupies a north and south belt, 

 between the meridians of 77° and 91° long. W. of Gr.) 

 extending north and south from Lake Superior to 

 Alabama, average lat., say 40 02 . On the opposite 

 side of the globe, this belt, prolonged in a great cir- 

 cle, will include the main iron belt of Asia. 



(£>) The iron of Europe is in a belt about (20) 

 twenty degrees or nearly 800 3 statute miles in width, 

 namely from long. 5 W. to long. 15 E., extending 

 north and south from Scandinavia to Tunis : thus 

 being about 90 distant from the American-Asiatic 

 belt. 



(c) The only other iron laid down in Cornell is 

 in a belt from near the Urals to a deposit in Persia, 

 half way between the European and the Central Asi- 

 atic iron belt, or about 45 ° distant from each of 

 these. 



(d) Dana mentions some iron in the region of 

 San Francisco, which would be about 45° west of the 

 Pennsylvania portion of the main United States belt. 



2. Manganese. — The localities given by Dana for 

 this metal would fall almost, if not entirely, within the 

 iron belts of North America and Europe : showing a 

 similar tendency to assume a paramagnetic direction. 



3. Platinum. — The chief localities of platinum, as 

 given in Dr. Dana's Manual of Mineralogy ; namely, 

 the Ural Mountains and North Granada, South Ame- 

 rica, as well as Canada and North Carolina, where 

 traces have been found, fall within the United States 

 iron belt. Borneo and places in Minas Gerses, Bra- 

 zil, where some platinum has been taken out, are very 

 slightly east of the above-named belt. 



4. Nickel and Cobalt. — Ores of these metals are 

 found, according to Dana, in Cornwall, Sweden, Nor- 

 way, France, Saxony and the United States (Missouri, 

 North Carolina, Pennsylvania) : all again within one 

 or other of the paramagnetic iron belts. Some nickel 

 found in New Caledonia would occupy a position very 

 nearly half way between the iron belt of Central Asia 

 and the iron of California. 



Without going into further details at present regard- 

 ing the paramagnetic metals and their ores, let us ex- 

 amine some of the 



II. DIAMAGNETIC METALS AND THEIR ORES. 



i. Gold. This metal cooling among the first on 

 the globe is found in old formations ; but appears to 

 be also injected into, or deposited in, the fractures 

 and fissures of rocks having a more recent age. The 

 earlier east and west ranges or belts, in which it 



2 A degree of longitude in latitude 40 is about 53 statute miles ; conse- 

 quently the width of the belt is nearly 750 miles. 



3 The average latitude of European iron being about 54" to 55° N., we 

 may call a degree equal to 40 statute miles, thus giving the above result. 



occurs more or less, often correspond, as already 

 stated, with parallels of latitude ; thus we find gold on 

 a belt of the parallels 55 to 60° N. lat., comprising 

 the gold of Alaska, Scotland, Sweden and the Urals ; 

 again in a belt ranging from lat. 45 to 50 N., em- 

 bracing" the gold of British Columbia, Washington 

 Territory and Oregon, of Lake Superior, Canada and 

 Nova Scotia, in North America. We find on the 

 same parallels or belt, in the eastern continent, the 

 gold of the Alps, Tyrol, Hungary and the Altai 

 Mountains. Another zone or belt, in about lat. 35 

 to 3 8° N., runs from California and Arizona, through 

 Georgia and North Carolina, and is prolonged through 

 Spain, Thibet, China and Japan. A more southerly 

 belt marks the gold of Central America and New 

 Granada (United States of Colombia, S. A.), also of 

 Western and Eastern Africa (about 5 N. of the 

 Equator), as well as of Ceylon, Java and Borneo. 

 The most southerly belt, in about lat. 22 to 32 S., 

 embraces the South American gold localities, the gold 

 washings of South Africa, the rich mines of Australia, 

 and almost includes the gold of New Zealand. 



In some cases, without making the belt so broad, 

 gold localities can be traced on one and the same 

 curve, using either the northern focus of each conti- 

 nent for a centre, or occasionally the more southern 

 continental focus. For instance, using the Boothia 

 Felix focus as a centre, an arc unites the gold of Ore- 

 gon with that of Canada, while from the Lake Superior 

 focus a curve sweeps from the gold of the Sierra Ne- 

 vada and the Sacramento Valley in California to that 

 of Georgia and North Carolina. 



2. Silver. The most noted localities for this useful 

 metal can be readily traced in North America, Europe 

 and Asia, on belts running east and west, often at 

 vertical intervals of about 4 to 5° apart, or say every 

 300 statute miles. Thus we have a belt from the 

 silver of Norway to that in the Urals ; then another, 

 from Montana, Idaho, Wyoming and Lake Superior 

 regions, continued through England, France and Sax- 

 ony to the Altai Mountains ; a third silver girdle runs 

 from California and Arizona, through Utah and Colo- 

 rado, thence to Spain. A fourth shows that of Mex- 

 ico on the same parallel with the silver of China. 

 Then come the rich mines of South America, in three 

 successive belts (that of Venezuela, of Brazil and of 

 Bolivia), with nothing to correspond in the eastern 

 continent. 



3. Copper can equally readily be traced along belts 

 on diamagnetic parallels ; such as one in Scandinavia 

 connecting with the Urals. A second, on the parallel 

 of the rich Lake Superior region takes in the copper 

 of Cornwall, of France, Thuringia, Hungary, Siberia, 

 China and Japan ; a third can be found embracing 

 the mines of Arizona, New Mexico, Tennessee and 

 North Carolina, also of the Island of Cyprus, of 

 Turkestan and Persia ; a fourth gives us the copper 

 of Cuba, Africa, Arabia and Hindostan, as shown in 

 map No. VIII, of Cornell's Phy. Geogr., by Stein- 

 wehr. Of the two copper belts in S. America, the 

 more Southerly is on the same parallel with the cop- 

 per of Australia. 



4. Tin (although sparingly distributed, except in 

 two or three localities) follows the same rule: First 

 belt, Massachusetts, New Hampshire, Cornwall (Eng- 

 land), Saxony, Austria, and Russia. Second belt, 



