JOHNSON'S

(REVISED)

UNIVERSAL CYCLOPÆDIA:

A SCIENTIFIC AND POPULAR

TREASURY

OF

USEFUL KNOWLEDGE.

ILLUSTRATED WITH MAPS, PLANS, AND ENGRAVINGS.

EDITORS-IN-CHIEF.

FREDERICK A. P. BARNARD, S. T. D., LL.D., L. H. D., M. N. A. S.,

PRESIDENT OF COLUMBIA COLLEGE, NEW YORK;

ARNOLD GUYOT, PH.D., LL.D., M. N. A. S.,

PROFESSOR OF GEOLOGY AND PHYSICAL GEOGRAPHY, COLLEGE OF NEW JERSEY.

ASSOCIATE EDITORS.

MARTIN B. ANDERSON, A. M., LL.D.,

President of the University of Rochester, N. Y.;
JOHN G. BARNARD, A. M., LL.D., M. N.A.S.,

Col. U.S. Engineers, Bvt. Major-Gen. U. S. A.;
C. F. CHANDLER, PH. D., M. D., LL.D., M. N. A. S.,
Prof. Anal. Chem., School of Mines, Columbia College;
AARON L. CHAPIN, A. M., S. T. D.,

President of Beloit College, Wisconsin;

HENRY DRISLER, A. M., LL.D.,

Jay Professor of Greek, Columbia College;
THEODORE W. DWIGHT, A. M., LL.D.,
Professor of Municipal Law, Columbia College;

OCTAVIUS B. FROTHINGHAM, A. M.,

Late Pastor Third Unitarian Society, N. Y. City;
THEODORE GILL, A. M., M. D., PH. D., M. N. A. S.,

Prof. of Zoology, Columbian University, Washington, D. C.;
ASA GRAY, M. D., LL.D., M. N. A. S.,

Fisher Professor of Natural History, Harvard University;
HORACE GREELEY, LL.D.,

Founder of the New York Tribune;
SAMUEL S. HALDEMAN, A. M., LL.D., M. N. A. S.,
Prof. of Comparative Philology in the Univ. of Penn.;
WILLIAM T. HARRIS, A. M., LL.D.,

Ed. of The Journal of Speculative Phil., St. Louis, Mo.;
JOSEPH HENRY, LL.D., M. N. Á. S.,

Late Secretary of Smithsonian Institution;
ROSWELL D. HITCHCOCK, A. M., S. T. D., LL.D.,
President of the Union Theol. Sem., New York;
CHARLES P. KRAUTH, A. M., S. T. D., LL.D.,

JOHN LE CONTE, A. M., M. D., LL.D.,

S. B. LUCE,

Prof. of Physics, Univ. of California;
Rear-Admiral, U. S. N. ;

GEORGE P. MARSH, LL.D., M. N. A. S.,

Late Minis. Plenipo. of U. S. at Rome, Italy;

JOHN S. NEWBERRY, M. D., LL.D., M. N. A. S.,
Prof, of Geology and Palæontology, Columbia College;
WILLARD PARKER, A. M., M. D., LL.D.,

Professor of Surgery, Columbia College, Med. Dept.;
WILLIAM G. PECK, A. M., LL.D.,
Professor of Astronomy and Mathematics, Columbia College;
JOHN D. PHILBRICK, LL.D., D. C. L.,
Late Supt. of Public Schools of Boston;
PHILIP SCHAFF, PH. D., S. T. D., LL.D.,

Baldwin Prof. of Sacred Lit., Union Theol. Sem., N. Y.;
JULIUS H. SEELYE, A. M., S. T. D., LL.D.,
President of Amherst College, Mass.;
AINSWORTH R. SPOFFORD, LL.D.,

Librarian of Congress;

WILLIAM STAUNTON, S. T. D.,
Founder and First Rect. of St. Peter's Church, Brooklyn, N. Y.;
ALEXANDER H. STEPHENS, A. M., LL.D.,

Of Georgia, Member 43d Congress, U. S. A.;
ABEL STEVENS, A. M., LL.D.,

Formerly Editor of the Methodist, New York;
THOMAS O. SUMMERS, S. T. D., LL.D.,

Late Professor of Syst. Theol., Vanderbilt Univ., Tenn.;
WM. P. TROWBRIDGE, A.M., PH.D., LL.D., M.N.A.S.,
Prof. of Engineering, Columbia College;

Vice-Provost of the University of Penn.;
THEODORE D. WOOLSEY, S. T. D., LL.D.,
Ex-President of Yale College, Conn.

ASSISTANT EDITORS.

PORTER C. BLISS, A. M., L. P. BROCKETT, A. M., M. D., George CHASE, LL.B., CLARENCE Cook,
PROF. E. D. HUDSON, JR., M. D., CLEMENS PETERSEN, A. M., JOHN N. POMEROY, LL.D.
WITH NUMEROUS CONTRIBUTIONS FROM WRITERS OF DISTINGUISHED EMINENCE IN EVERY DEPARTMENT
OF LETTERS AND SCIENCE IN THE UNITED STATES AND IN EUROPE.

Complete in Eight Royal Octavo Volumes, including Appendix,

VOL. VI.

ONION SALT.

(TESTIMONIALS AT THE END OF LAST VOLUME.)

NEW YORK:

A. J. JOHNSON & CO.,

11 GREAT JONES STREET, NEAR BROADWAY.

M. T. BROWN, DAVENPORT, IA.

MDCCCLXXXVI.

COPPER-PLATE MAPS ESPECIALLY ENGRAVED FOR JOHNSON'S CYCLOPÆDIA.

ENTERED ACCORDING TO ACT OF CONGRESS, IN THE YEAR ONE THOUSAND EIGHT HUNDRED AND EIGHTY-SIX, BY A. J. JOHNSON & CO., IN THE OFFICE OF THE LIBRARIAN OF CONGRESS, AT WASHINGTON.

ORGANIZATION OF THE EDITORIAL STAFF.

The following statement shows the subjects to which the different members of the Editorial Staff have severally given their more particular attention, not only in themselves preparing articles relating to those subjects, but also in securing contributions from others, and in carefully scrutinizing all such contributions with a view both to ensure accuracy and to exclude anything which might seem objectionable.

Mathematics, Applied Science, Protestant Episcopal Church, Education, etc. FRED. A. P. BARNARD.

Physical Geography, Foreign Geography, Climatology, etc.
Zoology, Comparative Anatomy, and Animal Physiology
Mechanics, Mechanical Engineering, etc. .

Military Engineering, Science and Material of War, Biographies, etc.
Botany and Vegetable Physiology

ARNOLD GUYOT.*

THEODORE GILL.

WILLIAM P. TROWBRIDGE.

Philosophical and Church Dogmatics; Lutheran Church-Biographies, etc. CHARLES P. KRAUTH.*

The names of the following gentlemen-J. G. Barnard, Horace Greeley, Arnold Guyot, S. 8. Haldeman, Joseph Henry, C. P. Krauth, George P. Marsh, Willard Parker, Alexander H. Stephens, Thomas O. Summers-have been, with justice, retained upon the Editorial Stoff, as their latest labors were given to this work.