CONTENTS 
I. Observations of the Second Comet of 1822, made at Rio de Janeiro. By 
Lieutenant (now Captain) William Robertson, R.N. Communicated 
in a Letter to Captain Basil Hall, F.R.S page 1 
II. On the performance of Fluid Refracting Telescopes, and on the applica- 
bility of this principle of construction to very large instruments. By 
Peter Barlow, Esq. F.R.S. Cor. Mem. Inst, of France, of the Imperial 
Academy of St. Petersburgh, &;c. 8§c 9 
III. Researches in Physical Astronomy. By John William Lubbock, Esq. 
V. P. and Treas. R.S 17 
IV. On the Transient Magnetic State of which various Substances are suscep- 
tible. By William Snow Harris, Esq. Communicated by Davies 
Gilbert, Esq. V.P.R.S. 67 
V. On the Nature of Negative and of Imaginary Quantities. By Davies 
Gilbert, Esq. V.P.R.S. 91 
VI. On the probable Electric Origin of all the Phenomena of Terrestrial Mag- 
netism ; with an illustrative Experiment. By Peter Barlow, Esq. 
F.R.S. Cor. Mem. Inst, of France, of the Imperial Academy of St. Pe- 
tersburgh, 8fc. <8fc 99 
VII. On the Equilibrium of Fluids, and the Figure of a Homogeneous Planet 
in a Fluid State. By James Ivory, A.M. F.R.S. Instit. Reg. Sc. Paris. 
Corresp. et Reg. Sc. Gottin. Corresp 109 
