ABBOTT.—ELEMENTARY THEORY OF THE TIDES: the Fundamental Theorems Demonstrated without Mathematics and the Influence on the Length of the Day Discussed. By T. K. Abbott, B.D., Fellow and Tutor, Trinity College, Dublin. Crown 8vo., 2s.

BALL.—Works by Sir ROBERT S. BALL, LL.D., F.R.S.

DE CAMPIGNEULLES.—OBSERVATIONS TAKEN AT DUMRAON, BEHAR, INDIA, during the Eclipse of the 22nd January, 1898, by a Party of Jesuit Fathers of the Western Bengal Mission. By the Rev. V. de Campigneulles, S.J. With 14 Plates. 4to., 10s. 6d. net.

GILL.—TEXT-BOOK ON NAVIGATION AND NAUTICAL ASTRONOMY. By J. Gill, F.R.A.S., late Head Master of the Liverpool Corporation Nautical College. 8vo., 10s. 6d.

HERSCHEL.—OUTLINES OF ASTRONOMY. By Sir John F. W. Herschel, Bart., K.H., etc. With 9 Plates and numerous Diagrams. 8vo., 12s.

JORDAN.—ESSAYS IN ILLUSTRATION OF THE ACTION OF ASTRAL GRAVITATION IN NATURAL PHENOMENA. By William Leighton Jordan. With Diagrams. 8vo., 9s.

LAUGHTON.—AN INTRODUCTION TO THE PRACTICAL AND THEORETICAL STUDY OF NAUTICAL SURVEYING. By John Knox Laughton, M.A., F.R.A.S. With 35 Diagrams. Crown 8vo., 6s.

LOWELL.—MARS. By Percival Lowell, Fellow American Academy, Member Royal Asiatic Society, Great Britain and Ireland, etc. With 24 Plates. 8vo., 12s. 6d.

MARTIN.—NAVIGATION AND NAUTICAL ASTRONOMY. Compiled by Staff Commander W. R. Martin, R.N. Royal 8vo., 18s.

MERRIFIELD.—A TREATISE ON NAVIGATION. For the Use of Students. By J. Merrifield, LL.D., F.R.A.S., F.M.S. With Charts and Diagrams. Crown 8vo., 5s.

PARKER.—ELEMENTS OF ASTRONOMY. With Numerous Examples and Examination Papers. By George W. Parker, M.A., of Trinity College, Dublin. With 84 Diagrams. 8vo., 5s. 6d. net.

WEBB.—CELESTIAL OBJECTS FOR COMMON TELESCOPES. By the Rev. T. W. Webb, M.A., F.R.A.S. Fifth Edition, Revised and greatly Enlarged by the Rev. T. E. Espin, M.A., F.R.A.S. (Two Volumes.) Vol. I., with Portrait and a Reminiscence of the Author, 2 Plates, and numerous Illustrations. Crown 8vo., 6s. Vol. II., with numerous Illustrations. Crown 8vo., 6s. 6d.