CONTENTS 
I. The Bakerian Lecture . — On certain Phenomena of Voltaic Ignition and the De- 
composition of Water into its constituent Gases hy Heat. By W. R. Grove, 
Esq., M.A. , F.R.S page 1 
II. Supplementary Paper on certain Phenomena of Voltaic Ignition , and the Decom- 
position of Water into its Constituent Gases hy Heat. By W. R. Grove, 
Esq., M.A., F.R.S 17 
III. Microscopic Observations on the so-called Vesicular Vapours of Water, as existing 
in the Vapours of Steam, and in Clouds, &fc. By A. Waller, Esq., M.D. 
Communicated by P. M. Roget, M.D., Sec. R.S 23 
IV. Quelques recherches sur V Arc Voltaique, et sur V influence quexerce le Magndtisme 
soit sur cet arc soit sur les corps qui transmettent les Courants Electriques Dis- 
continus. 
Researches on the Voltaic Arc, and on the influence which Magnetism exerts 
both on this Arc and on bodies transmitting interrupted Electric Currents. By 
M. Auguste De la Rive, Professor in the Academy of Geneva, Foreign Member 
of the Royal Society, Corresponding Member of the Academy of Sciences at 
Paris, Sfc. 8$c 31 
V. On the Lunar Atmospheric Tide at St. Helena. By Lieut. -Colonel Edward Sabine, 
R.A., For. Sec. R.S. 45 
VI. On the Diurnal Variation of the Magnetic Declination at St. Helena. By Lieut. - 
Colonel Edward Sabine, R.A., For. Sec. R.S. 51 
VII. On the Automatic Registration of Magnetometers, and other Meteorological 
Instruments, by Photography. By Charles Brooke, M.B., F.R. C.S.E. Com- 
municated by G. B. Airy, Esq., F.R.S., Astronomer Royal 59 
VIII. On the Automatic Registration of Magnetometers, and other Meteorological Instru- 
ments, by Photography. Supplement. By Charles Brooke, M.B., F.R.C.S.E. 
Communicated by G. B. Airy, Esq., F.R.S., Astronomer Royal .... 69 
IX. On the Proper Motion of the Solar System. By Thomas Galloway, Esq., M.A., 
F.R.S. 79 
X. On Photographic Self -registering Meteorological and Magnetical Instruments. 
By Francis Ronalds, Esq., F.R.S. Ill 
