664 
further statutory powers no accurate account of 
the quantity and value can be given. Thanks 
to the courtesy of the owners, who have fur- 
nished returns voluntarily, accurate statistics of 
the output of the shallow ironstone quarries of 
the Midlands have been secured; and in like 
manner the output of salt from brineworks has 
been calculated. The exports and imports of 
each of the principal minerals, furnished by the 
Board of Customs, are given after the tables of 
production, and in several cases information as 
to distribution, supplied by railway and naviga- 
tion companies, is added. Lists of smelters of 
the principal metallic ores follow the export 
and import tables, and in the case of iron the 
quantity of ore and coal used in the blast 
furnaces, and the make of pig iron, have been 
ascertained from voluntary returns furnished to 
the Home Office by the owners. The volume 
includes a table of the mines inspection districts, 
with the names and addresses of the inspectors 
of mines, assistant inspectors, secretaries to 
boards for examinations, and the Clerk of 
Mineral Statistics. The return also supplies a 
general summary of the value of minerals ob- 
tained from the colonies. The figures for 1895 
were: Africa and Mediterranean, £5,506,739 : 
Asia, £5,874,144; Australasia, £13,919,068 . 
Europe, £139,289 ; North America, £3,842,586; 
South America, £446,695; and British West 
India Islands, £101,550; total, £29,830,071, as 
compared with £28,765,009 in 1894. 
UNIVERSITY AND EDUCATIONAL NEWS. 
ProFESSOR JAMES M. CRAFTs has been elected 
President of the Massachusetts Institute of 
Technology. Professor Crafts holds the chair 
of organic chemistry in the Institute and has 
been the acting president since the death of 
General Walker. 
At Cambridge University Mr. J. B. Peace, 
M.A., Fellow of Emmanuel College, has been 
appointed demonstrator in mechanism and 
applied mechanics for five years, and Mr. H. 
Higgins, M.A., of King’s College, has been re- 
appointed demonstrator of anatomy for five 
years. 
Dr. Mouser, of Gottingen, has been ap- 
pointed professor of mechanical engineering in 
the Technological Institute at Dresden 
SCIENCE. 
{N.S. Von. VI. No. 148. 
THE New York City Board of Superintend- 
ents hold an examination for principalships of 
grammar schools on November 3d, 5th and 8th, 
which are open to candidates from any part of 
the United States having an experience of ten 
years in teaching. The salaries are from $2,500 
to $3,500 per annum. 
DISCUSSION AND CORRESPONDENCE. 
LEWIS ON THE DIAMOND. 
In two papers* recently published Mr. 
George F. Kunz has reviewed ‘Papers and 
notes on the genesis and matrix of the dia- 
mond by the late Henry Carvill Lewis.’ In 
each he attributes to Lewis the theory that 
South African diamonds have resulted from 
the intrusion of igneous rocks into and through 
carbonaceous shales, and the crystallization of 
the carbon throughout the rock as it cooled, 
from hydrocarbons distilled from the shale that 
had been broken through. In his communica- 
tion to SCIENCE, however, Mr. Kunz admits 
that in these papers Lewis does not distinctly 
assert that the shales are the origin of the car- 
bon. Mr. Kunz derives his authority for his 
representations on this point from conversa- 
tions with Lewis ten years or more ago. 
It seems to me that Mr. Kunz does Lewis a 
serious injustice. Had the latter wished to 
commit himself in print to this theory it would 
have been easy for him to express himself in 
terms as positive as those which Mr. Kunz em- 
ploys. Far from doing so he appears to sup- 
port a radically different theory, viz., that the 
diamonds are phenocrysts and an integral part 
of the lava. In the following paragraphs I 
shall quote every phrase in these two papers 
which bears on the subject, the rest of the text 
consisting of lithological discussions and the 
like. 
In his first paper, page 6, Lewis properly 
attributed the hypothesis of the derivation of 
the carbon from the shales to Mr. E. J. Dunn.{ 
Lewis expresses no assent to this hypothesis, at 
least in this connection, and merely comments: 
* Production of Precious Stones in the United States, 
U.S. Geol. Survey, Mineral Resources, 1896; and this 
JOURNAL, Sept. 17, 1897. 
+ Quar. Jour. Geol. Soc., Vol. 37, 1881, p. 610. 
