GENESIS OF THE DIAMOND.
Editor Popular Science Monthly:
SIR: An excellent notice of Prof. A. E. Foote's paper on Diamonds in Meteorites has newly been forwarded to me, and, as it has apparently aroused no little interest in the general public as well as in scientific circles, may I take the liberty of calling attention to the following facts through the pages of The Popular Science Monthly, to which I have for some years past been a subscriber?
In September, 1886, my husband, the late Prof. H. Carvill Lewis, read before the Birmingham meeting of the British Association for the Advancement of Science a paper on A Diamantiferous Peridotite and the Genesis of the Diamond, a small specimen of which he had recently discovered, in situ, in a piece of the peridotite rock underlying the tenacious "blue clay" of the Kimberley mines. He further stated that this "blue clay" was found upon subsequent analysis to be merely the same peridotite rock in a high state of decomposition. The process of freeing the diamonds from the "blue clay," in which they are scattered about like plums in a pudding, is so well known that it need not be dwelt upon.
The peridotite in question is an altered lava, filling the neck of an ancient volcano, which burst its way through a rich deposit of carbonaceous shales. Numberless fragments of this shale, of varying size, were found scattered throughout the peridotite, and Prof. Lewis held that it was the pure carbon from these, which, liberated by the intense heat, and crystallizing slowly out under enormous pressure, had formed the diamonds.
In September, 1887, my husband delivered another address at the Manchester meeting of the British Association for the Advancement of Science, entitled The Matrix of the Diamond, in which he described in full the chemical changes and metamorphoses which the peridotite and its constituents had undergone in passing into the "blue clay." An abstract of this paper was distributed among the geologists present, and was afterward published in the Report of the Association for 1887.
At the close of this paper Prof. Lewis remarked that "if his hypothesis concerning the origin of diamonds was correct, they would certainly be found in meteorites"; but it was not until December of the same year (1887) that he received, through the courtesy of Mr. George Frederick Kunz, of New York, a small fragment of meteoric ore, in the larger portion of which two Russian geologists had newly reported the finding of several minute diamonds. Mr. Kunz found thirteen diamonds, I believe, in his share of the meteorite, and my husband found three; but in both cases all were microscopic. This discovery was soon after announced at the Academy of Natural Sciences in Philadelphia, and a short notice of it was published with the title Diamonds in Meteorites.
To Prof. A. E. Foote, therefore, belongs the honor of finding the first diamonds in American meteorites, and not of discovering that abstract possibility or its first realization.
The manuscript for a comprehensive article on The Origin and Matrix of the Diamond, embodying Prof. Carvill Lewis's Birmingham and Manchester addresses, and the subsequent investigations made by him as to the origin of that gem in the southeastern portion of the United States, is now in the hands of Prof. G. H. Williams, of the Johns Hopkins University, and will, it is hoped, soon be ready for the press.
In view of the foregoing statements, it seems open to question whether the position of the meteoric fragments on the side of an old volcanic crater was not an accidental one, which at all events calls for further investigation before those outside the charmed circle of scientific workers are willing to accept so remarkable a hypothesis as to the origin of our terrestrial diamonds.
| I am, with respect, |
| Faithfully yours,Julia F. Lewis. |
| Heidelberg, January 29, 1892. |
MORE ABOUT THE PENIKESE SCHOOL.
Editor Popular Science Monthly:
President Jordan's interesting article on Agassiz at Penikese forms a valuable contribution to the history of marine laboratories in this country, in giving a list, unfortunately incomplete, of those in attendance at the school during its first session. Might it not be possible to complete the list for both years during which the school was in existence? Such a list would form a valuable appendix to the interesting account of the school given by Mrs. Agassiz in her Life and Letters of Louis Agassiz.
President Jordan does not mention in his article the fact that the laboratory building no longer exists. It was destroyed by fire during last summer. A week before its destruction I visited Penikese with a small party from the Marine Biological Laboratory of Wood's Holl, Mass., and had the pleasure of meeting the present owner of the island, Mr. G. S. Horner, of New Bedford, who kindly gave us permission to carry away for the Ma-
