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, and 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 I’kof. Richard Owkn, M.R., 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 dia?nag?ietically, 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 diamggnetic 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 near 
the median line of each Continent , and are found i?i 
older rocks as well as newer. Diamagnetic ?netals 
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 atid 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 permian rocks, showing that, although 
occurring in subcarboniferous limestone, they were much later in origin.” 
