Diamonds
of the World," Hamlin's "Leisure Hours among the Gems," Williams's
"Diamond Mines of South Africa," Boutan's "Le Diamant," and Tassin's "
Descriptive Catalogue of the Collections of Gems in the United States
National Museum," 1902.
To
several individuals the writer is under obligations for valuable
assistance. The Foote Mineral Company of Philadelphia kindly loaned
numerous specimens for illustrating the colored plates. Mr. Frederick
J. Essig, of Chicago, rendered similar aid in loaning specimens of cut
stones and photographs, and also gave freely information regarding many
practical points.
To
Dr. Orville A. Derby, of the Geological Survey of Brazil, Dr. J. H.
Pratt, Mr. A. C. Lane, Dr. A. C. Hamlin, Ernest Schernikow and Prof. J.
P. Iddings the writer is also under obligation for the loan of
photographs ; and to Dr. P. Groth, of Munich, for the loan of a
half-tone plate.
Mr.
William K. Higley has given the details of preparation of the plates
and typographical execution of the work much careful attention, and the
writer is indebted to him for other assistance and courtesies.
In
conclusion, it is the writer's hope that this work may lead to a wider
knowledge of gems, a more intelligent use of them and an admission to
their charmed circle of some substances now shut out because little
known.