CONTENTS, 
PART II. 
X. On Hyperjacobictn Surfaces and Curves. By William Spottiswoode, M.A., LL.T) 
Treas. B.S. page 351 
XI. On a new Form of Tangential Equation. By John Casey, LL.T)., F.B.S., 
M.B.L.A., Professor of Mathematics in the Catholic University of Lreland 36T 
XII. On the Bicircular Quartic. — Addition to Professor Casey’s Memoir “ On a new 
Form of Tangential Equation.” By A. Cayley, LL.T)., F.B.S., Sadlerian Pro- 
fessor of Pure Mathematics in the University of Cambridge ..... 441 
XIII. Contributions to Terrestrial Magnetism. — No. XV. By General Sir Edward 
Sabine, B.A . , K.C.B., F.B.S. . 461 
XIV. On Friction between Surfaces moving at Low Speeds. By Fleeming Jenkin, 
F.B.SS.L. & E., Professor of Engineering in the University of Edinburgh, and 
J. A. Ewing 509- 
XV. On the Structure and Development of the Skull in the Urodelous Amphibia . — Part I. 
By William Kitchen Parker, F.B.S. 529 
XVI. Besidual Charge of the Leyden Jar. — Dielectric Properties of different Glasses ~ 
By J. Hopkinson, M.A., D.Sc. Communicated by Professor Sir William 
Thomson, F.B.S. 599 
XVII. On the Physiological Action of the Bark of Erythrophleum Guinense, generally 
called Casca, Cassa, or Sassy Bark. By T. Lauder Brunton, M.D., F.B.S., 
and Walter Pye, Esq 627 
XVIII. Further Observations on the Locomotor System of Medusae. By George J. 
Romanes, M.A., F.L.S., &c. Communicated by Professor Huxley, LL.D 
Sec. B.S 659 
Lndex 
755 
