CONTENTS. 
PAET I. 
I. The Diurnal Variations of the Wind and Barometric Pressure at Bombay . By 
F. Chambers. Communicated by Charles Chambers, F.B.S . , Director of the 
Colaba Observatory , Bombay page 1 
I*. On the Osteology of the Hyopotamidse. By Dr. W. Kowalevsky. Communicated 
by Professor Huxley, Sec. B.S. 19 
II. The Bakerian Lecture. — On the Structure and Development of the Skull in the 
Salman (Salmo salar, L.). By William Kitchen Parker, F.B.S. ... 95 
III. Volcanic Energy : an attempt to develop its true Origin and Cosmical Relations. 
By Robert Mallet, A.M., C.E., M.B.I.A., F.B.S. 147 
IV. On Curvature and Orthogonal Surfaces. By A. Cayley, LL.D., F.B.S., Sadlerian 
Professor of Mathematics in the University of Cambridge 229 
V. Researches in Spectrum-Analysis in connexion with the Spectrum of the Sun. — No. I. 
By J. Norman Lockyer, F.B.S. 253 
VI. Researches on the Atomic Weight of Thallium. By William Crookes, F.B.S., 
Ac 277 
VII. Magnetical Observations in the Britannia and Conway Tubular Iron Bridges. By 
Sir George Biddell Airy, K.C.B., P.B.S., Astronomer Royal .... 331 
VIII. Magnetic Survey of Belgium in 1871. By the Rev. Stephen J. Perry. Com- 
municated by General Sir Edward Sabine, F.B.S. 341 
IX. On the Union of Ammonia Nitrate with Ammonia. By Edward Divers, M.D. 
Communicated by Professor Odling, M.B., F.B.S 359 
