[ iv ] 
changes which it undergoes during a part of the Metamorphoses of the 
Insect. By George Newport, Esq. Communicated by P. M. Roget, 
M.D. Sec. R.S . page 383 
XIX. On the Correction of a Pendulum for the Reduction to a Vacuum: 
together with Remarks on some anomalies observed in Pendulum experi¬ 
ments. By F. Baily, Esq. F.R.S . 399 
XX. An Account of the Magnetical Experiments made on the western coast of 
Africa, 1830-1, by Commander Edward Belcher, of H. M. S. TEtna. 
Communicated by the Rev. George Fisher, F.R.S. through Captain 
Beaufort, R.N. F.R.S . 493 
XXL Observations on the Anatomy and Habits of Marine Testaceous Mollusca, 
illustrative of their mode of feeding. By Edward Osler, Esq. Com¬ 
municated by L. W. Dillwyn, Esq. F.R.S . 497 
XXII. On the Mammary Glands of the Ornithorhynchus paradoxus. By 
Mr. Richard Owen. Communicated by J. FI. Green, Esq. F.R.S. 51/ 
XXIII. On the Water-Barometer erected in the Hall of the Royal Society. By 
J. F. Daniell, Esq. F.R.S. Professor of Chemistry in King’s College , 
London . 539 
XXIV. Hourly Observations on the Barometer; with experimental investigations 
into the phenomena 'of its pjeriodical oscillation. By James FIudson, 
Assistant Secretary and Librarian to the Royal Society. Communicated 
by John William Lubbock, Esq. M.A. Vice President and Treasurer 575 
XXV. Note on the Tides in the Port of London. By J. W. Lubbock, Esq. 
V.P. and Treas. R.S . 595 
XXVI. Researches in Physical Astronomy. By J. W. Lubbock, Esq. V. P. 
and Treas. R.S . 601 
Index ... 609 
Appendix. 
Presents received by the Royal Society, from Nov. 18 th 1830 to June 1 Qth 1831. 
Meteorological Journal kept at the Apartments of the Royal Society, by order 
of the President and Council. 
