OF

METALLURGY.

BY

W. C. ROBERTS-AUSTEN, C.B., F.R.S.,

ASSOCIATE OF THE ROYAL SCHOOL OF MINES; CHEMIST AND ASSAVER OF THE ROYAL MINT; PROFESSOR OF METALLURGY IN THE ROYAL COLLEGE OF SCIENCE, WITH WHICH

THE ROYAL SCHOOL OF MINES IS INCORPORATED.

THIRD EDITION, REVISED AND ENLARGED.

ONE OF A SERIES OF TREATISES WRITTEN BY
ASSOCIATES OF

THE ROYAL SCHOOL OF MINES.

LONDON:

CHARLES GRIFFIN & COMPANY, LIMITED,

EXETER STREET, STRAND.

1894.

[All rights reserved.]

"I rather open, than discover things."

MONTAIGNE'S ESSAYS (1580).

"To know

Rather consists in opening out a way

Whence the imprisoned splendour may escape,

Than in effecting entry for a light
Supposed to be without."

BROWNING'S "PARACELSUS" (1835).

TIMIA OL

AIMBOTLIAO

TO THE

HON. SIR C. W. FREMANTLE, K.C.B.

DEPUTY-MASTER OF THE MINT.

FOR more than twenty years there have been few things, except this dedication, about which I have not consulted you. The book embodies the results of many investigations conducted in the Mint during that period, and the encouragement you have always given to research, and your interest in its progress, have been most helpful. This is, however, only one of the many reasons why this slender gift is so gladly offered to you, as it is now, with the sincere friendship of

THE AUTHOR.

390325

PREFACE TO THE THIRD EDITION.

THE Author is much gratified to find that the effort made in the earlier editions of this book to afford a basis for the study of Metallurgy by systematically arranging facts connected with metals and with their extraction from the ore has been welcomed by students, by practical metallurgists, and by chemists. In the present edition the scope of the work has been extended, and a hundred new pages have been added to the volume. The growing importance of Molecular Mechanics in relation to Metallurgical problems, has rendered it necessary to insert a new chapter on Thermochemistry. A special chapter has also been added in which the mode of studying the micro-structure of metals and alloys is dealt with. Large additions would have been made to the portion which relates to alloys, but it was considered better that a special treatise should be devoted to them. This is in an advanced stage of preparation, and, with the series of treatises which are being written under the Author's guidance, for the most part by Associates of the Royal School of Mines who have special knowledge of individual metals, will, it is hoped, serve to make the literature of Metallurgy adequately represent the progress which has been made in recent years.

March, 1894.