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THE POPULAR SCIENCE MONTHLY 



CORRESPONDENCE. 



GENESIS OF THE DIAMOND. 

 Editor Popular Science Monthly : 



SIR: An excellent notice of Prof. A. E. 

 Foote's paper on Diamonds in Meteor- 

 ites 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 at- 

 tention to the following facts through the 

 pages of The Popular Science Monthly, to 

 which I have for some years past been a sub- 

 scriber ? 



In September, 1886, my husband, the late 

 Prof. H. Carvill Lewis, read before the Bir- 

 mingham 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 tena- 

 cious " 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 pud- 

 ding, 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 deliv- 

 ered 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 metamor- 

 phoses which the peridotite and its constitu- 

 ents had undergone in passing into the " blue 

 clay." An abstract of this paper was dis- 

 tributed among the geologists present, and 

 was afterward published in the Report of 

 the Association for 1887. 



At the close of this paper Prof. Lewis re- 

 marked 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 geolo- 

 gists had newly reported the finding of sev- 



eral minute diamonds. Mr. Kunz found thir- 

 teen diamonds, I believe, in his share of the 

 meteorite, and my husband found three ; but 

 in both cases all were microscopic. This dis- 

 covery was soon after announced at the Acad- 

 emy 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 realiza- 

 tion. 



The manuscript for a comprehensive ar- 

 ticle on The Origin and Matrix of the Dia- 

 mond, embodying Prof. Carvill Lewis's Bir- 

 mingham and Manchester addresses, and the 

 subsequent investigations made by him as 

 to the origin of that gem in the southeast- 

 ern 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 inves- 

 tigation before those outside the charmed 

 circle of scientific workers are willing to ac- 

 cept 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 contri- 

 bution 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 exist- 

 ence? 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 de- 

 struction 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- 



