226 



SCIENCE. 



tion of microscopists to the subject. We suggest that 

 they should give some expression of opinion, if they 

 desire the integrity of this Society. For ourselves, we 

 shall strongly support the maintenance of the Amer- 

 ican Society of Microscopists, on account of our de- 

 cided faith in its usefulness, and necessity for its ex- 

 istence, and for the reason also, that no real cause has 

 been shown for its disbandment. 



Taking the charges of the editor of the American 

 Monthly Microscopical Journal in the order presented, 

 we would say : ist. That we have the authority of the 

 late President, Professor H. L. Smith, that the Society 

 has received sufficient support to make it a success 

 2d. That the Society has been unexceptionally fortu- 

 nate in the selection of officers, that they have proved 

 themselves to be experienced men, zxi&have "directed 

 properly." 3d. That the Society does not deem it neces- 

 sary to meet in conjunction with the A. A. A. S., and 

 has voted down all resolutions for so doing. The asser- 

 tion to the contrary is therefore perfectly gratuitous, 

 and the fact that those who propose it, also made it a 

 reason for breaking up the Society, has the appearance 

 of a desire to lead the Society to such an end. 4th. 

 The demand made upon the Society by one of its 

 members, to show cause why it should exist, appears 

 slightly presumptuous and ill-timed. As a suggestion 

 before the establishment of the society it might have 

 had some weight, but after the third annual meeting, 

 and the congratulations of its President on its success, 

 the proposition is unseasonable. We would remind 

 the editor of the American Monthly Microscopical 

 Journal, when he challenges the American Society of 

 Microscopists to show the raisen d'etre for its exist- 

 ence, that fifty delegates, representing the microscopists 

 of the United States, in his presence passed a resolu- 

 tion in the following words : " We think it desirable to 

 have a National Organization for the promotion of 

 Microscopical Science." We consider this a conclusive 

 answer to the present querest, and to all others who 

 in future raise such a question. 



The article we have referred to states, that " if the 

 American Society of Microscopists does not decide to 

 meet next year in convention with the A. A. A. S., at 

 Cincinnati, that the next meeting will be its last." As 

 the writer also states, that if it does so meet, the 

 necessity will arise for it to be " disorganized," and as 

 one of these alternatives is inevitable, the fate of the 

 society would appear to be sealed. 



As we believe these difficulties to be purely im- 

 aginary, we are ready to grant the American Society of 

 Microscopists a long term of existence, and a future 

 of utility and progress. If any of our readers are of a 

 contrary opinion, our columns are open for an expres- 

 sion of their views. 



LAW ACCORDING TO WHICH THE METALS, 

 AND THEIR ORES, CAME TO, OR NEAR 

 TO, THE SURFACE OF THE EARTH. 

 By Prof. Richard Owen, M.D., LL.D. 



In the abstract of a paper read before the A. A. A. 

 S., which appeared in the issue of "Science" for Sep- 

 tember 25, 1880, allusion was made, in the closing 

 paragraph, to the connection between the law of land- 

 forming and that of metallic development. 



We might reasonably expect that the metals re- 

 quiring temperatures from 2000 degrees to over 2500 

 degrees F. to melt them (such as iron and gold) would 

 be the first to solidify, as our earth cooled ; and there- 

 fore more likely to exist among older rocks than such 

 metals as zinc, lead 1 and tin, which melt at a com- 

 paratively low temperature ; and consequently could 

 not become solid until the earth's crust had cooled to 

 773 degrees, 612 degrees, and 442 degrees, the melt- 

 ing points respectively of these metals. Such we find 

 to be the fact. Furthermore, Faraday demonstrated 

 that all substances, when suspended freely between 

 the jaws of a powerful horseshoe magnet, would place 

 themselves either paramagnetically , the same as iron 

 and some other metals, or diamagnetically, the same 

 as bismuth and numerous other bodies ; and the mag- 

 netism developed, for the time being, in that horse- 

 shoe magnet, may be, and often is, produced by pow- 

 erful currents of electricity. 



It has been proved that there are constantly cur- 

 rents of electricity passing in the earth's crust, chiefly 

 in an opposite direction from the earth's revolution, 

 perhaps therefore operating mainly in causing a freely 

 suspended needle to place itself at right angles to the 

 plane of those so-called currents. 



It seems therefore, further, not unreasonable to ex- 

 pect that metals, when about to solidify, if free to 

 permeate cavities in all directions, should assume, rela- 

 tively to these currents of electricity, respectively 

 either a paramagnetic or a diamagnetic position. Such 

 seems in reality to have been the case: Iron, manga- 

 nese, platinum, nickel, cobalt (and probably other 

 paramagnetic bodies, but time has not permitted this 

 latter investigation) will be found chiefly occupying 

 north and south belts, corresponding pretty generally 

 with meridians, while gold, silver, copper, tin, lead, 

 zinc, antimony, bismuth and other diamagnetic bodies 

 will be found in east and west belts, sometimes on 

 regular parallels, of which the terrestrial north pole 

 is the centre, sometimes in east and west curves, having 

 one or other of the Continental foci (pointed out in 

 the law of land-forming) as their centre. The appa- 

 rent law, then, briefly formulated, may be thus ex- 

 pressed : 



The paramagnetic metals, in consolidating, arranged 

 themselves along north and south belts, usually tiear 

 the median line of each Continent, and are found in 

 older rocks as well as newer. Diamagnetic metals 

 are most commonly to be found in belts, not necessarily 

 continuous, but running more or less east and west, 

 end except perhaps in the case of gold, silver and cop- 



1 Although lead is found sometimes in silurian and carboniferous rocks, 

 yet Dr. Dana shows (at page 148 of his Manual of Mineralogy) that such 

 is not its true age. Speaking of Galena, he says: " In Derbyshire. Eng- 

 land, the deposits contain fossils of pcrmian rocks, showing that, although 

 occurring in subcarbonifcrous limestone, they were much later in origin." 



