IX. An Introductory Memoir upon Quantics. By Arthur Cayley, Esq. page 245 
X. On the Functions and Structure of the Rostellum of Listera ovata. By J. D. 
Hooker, 31. D., F.R.S. 8§c 259 
XI. An Account of the Organic Chemical Constituents or Immediate Principles of 
the Excrements of Man and Animals in the Healthy State. By W. Marcet, 
M.D., F.C.S., formerly President of the Edinburgh Medical Society, Corre- 
sponding Member of the Socidte' de Biologie of Paris, and Member of the 
Parisian Medical Society. Communicated by Francis Marcet, Esq., F.R.S. , 
Geneva 265 
XII. On the Effect of the Pressure of the Atmosphere on the 31ean Level of the Ocean. 
By Captain Sir James Clark Ross, R.N., D.C.L., F.R.S. fyc 285 
XIII. On the frequent occurrence of Indigo in Human Urine, and on its Chemical, 
Physiological, and Pathological Relations. By Arthur Hill Hassall, M.D. 
Lond ., Member of the Royal College of Physicians, Physician to the Royal Free 
Hospital, 8fc. &fc. Communicated by Professor Sharpey, Sec. R.S. . . 297 
XIV. On certain Properties of square numbers and other quadratic forms, with a Table 
of odd numbers from 1 to 191, divided into 4, 3 or 2 square numbers, the 
algebraic sum of whose roots ( positive or negative ) may equal l, by means of 
which Table all the odd numbers up to 9503 may be resolved into not exceeding 
4 square numbers. By Sir Frederick Pollock, F.R.S., Lord Chief Baron 31 1 
XV. On the Thermal Effects of Fluids in Motion. — Part II. By J. P. Joule, F.R.S., 
and Professor W. Thomson, M.A., F.R.S 321 
Index 365 
Appendix. 
Presents 
[ i ] 
