454 
this rock bears marked resemblance both in 
structure and contents, and the others from 
well-known occurrences in terrestrial volcanic 
rocks. 
The third section of the volume is occupied 
with a detailed account, from specimens and 
notes of Professor Lewis, of the two other 
known occurrences of Kimberlite, at Syracuse, 
N. Y., and Willard, Ky. The identity of these 
with the African rock, in almost all particulars, 
is remarkable, and as they form definite eruptive 
dikes, Professor Lewis’ view as to the latter is 
strongly confirmed. 
It remains only to call attention to other and 
later facts which tend to bear out the views pre- 
sented in this remarkable posthumous article. 
The presence of a residual hydrocarbon in the 
rock of the African diamond mines was shown 
by an interesting and important observation of 
Sir Henry E. Roscoe (Proc. Lit. and Phil. Soc. 
of Manchester, XXIV., 1885, p. 5), which is al- 
luded to by Professor Lewisin his second paper, 
and has frequently been cited in discussions of 
the subject. He found that the ‘blue-ground’ 
on treatment with hot water yielded an aro- 
matic hydrocarbon, which he was able to sepa- 
rate by digesting the ‘blue-ground’ with ether 
and evaporating the solution. It then appeared 
as a crystalline aromatic solid, burning with a 
smoky flame (showing it rich in carbon), volatile, 
and melting at 50° C. 
The bearing of this fact upon Professor Lewis’ 
theory is clear. It indicates that the igneous 
rock, breaking through the highly carbonaceous 
Karoo shales (387.50 p. ¢. of carbon ; Whitfield, 
U.S. Geological Survey ; Gems and Prec. Stones 
North America, 1889, p. 33) became charged 
with volatilized hydrocarbons distilled from the 
shale, and that in cooling these had erystallized 
partly into diamonds and partly into the many 
carbonadoes, larger and smaller, which are dis- 
tributed through the rock. Professor Roscoe’s 
material strongly suggests this theory, which, 
indeed, he himself independently propounded. 
In 1886 a meteorite fell at Novo Urei (Sep- 
tember 22d) in the province of Pensa, Russia, 
which was found to contain about 1 per cent. of 
diamond carbon, in the form of gray particles.* 
* Daubreé’s discussion of the analogy of the occur- 
rence of the diamond in the meteorites and in the 
SCIENCE. 
[N.S Vou. VI. No. 142. 
In 1887 Mr. Fletcher (Mineralogical Magazine, 
7, 121) described the new mineral ‘ Cliftonite’ 
—a black substance with a hardness of 2.5 and 
a density of 2.12, occurring in cubes with faces 
of the dodecahedron or tetrahexahedron in the 
meteorite of Youndegin, West Australia. This 
suggested a graphitic alteration of diamond—a 
view taken by Brezina (Ann. Mus. Wien, IV., 
102, 1889) regarding this new species and cer- 
tain graphitic crystals of cubic type, observed 
long before in the Arva meteorite and regarded 
as pseudomorphs after pyrite by Haidinger 
(Pogg., 67, 487, 1846), but later by Rose, as after 
diamond (Beschr. Meteor., 40, 1864). Similar 
crystals were also known in the Sevier iron of 
Cocke county, Tenn. 
In 1891 the discovery of diamond, or at least 
of diamond carbon, in some quantity in the 
meteoric iron of Cafion Diablo, Arizona, was 
announced by the late Professor A. E. Foote 
(Amer. Jour. Science, Vol. XLII., July, 1891, pp. 
413-417) and Dr. George A. Koenig. In July, 
1892 (SctENCE, p. 15), Dr. O. W. Huntington 
gave further experiments on the same material, 
confirming the decisions of Professors Foote and 
Koenig; and in December of the same year 
similar results were published by M. C. Friedel 
(Bulletin de la Soc. Francaise de Mineralogie, No. 
9, p. 258). A crucial test was then proposed 
by G. F. Kunz, of New York, and carried out 
in the presence of Dr. Huntington, at the 
World’s Fair at Chicago, September 11, 1893, 
viz., the cutting of polished faces on pieces of 
diamond with some of the carbon powder from 
the cavities of the Cafion Diablo meteorite 
(Amer. Jour. Sci., Vol. XLVI., December, 1893; 
and Min. Resources U. 8., 1893, pp. 683-685). 
In the meantime Professor Henri Moissan, 
of Paris, had been making his now celebrated 
experiments on the artificial production of 
diamonds from the cooling, under extreme 
pressure, of highly carbonated iron fused in a 
specially constructed electric furnace (Mineral 
Resources U. §., 1895, pp. 903-904). 
All these facts taken together form a remark- 
able series of confirmatory evidence of the 
views advocated by our late countryman in re- 
South African Kimberlite was the next important 
paper on this subject. (Comptes Rendus, 110-18, 
1890.) 
