CONTENTS 
I. The Bakerian Lecture. — On the manufactare of Glass for optical purposes. 
By Michael Faraday, Esq. F.R.S. 8§c page 1 
II. Account of Levellings carried across the Isthmus of Panama, to ascertain 
the relative height of the Pacific Ocean at Panama, and of the Atlantic 
at the mouth of the river Chagres ; accompanied by Geographical and 
Topographical Notices of the Isthmus. By John Augustus Lloyd, Esq. 
Communicated by Captain Sabine, Secretary of the Royal Society. . 59 
III. On the law of the partial polarization of light by reflexion. By David 
Brewster, LL.D. F.R.S. L. 8$ E. 69 
IV. A Report on the stomach of the Zariffa. By Sir Everard Home, Bart., 
Vice-President of the Royal Society 85 
V. On the production of regular double refraction in the molecules of bodies 
by simple pressure ; with observations on the origin of the doubly re- 
fracting structure. By David Brewster, LL.D. F.R.S. L. 8$ E. . 8 7 
VI. Experiments on the influence of the Aurora Borealis on the magnetic needle. 
% the Reverend James Farquh arson, F.R.S. Minister of Alford, 
Aberdeenshire. In letters addressed to Captain Edward Sabine, Secretary 
of the Royal Society 97 
VII. Remarks on several icebergs which have been met with in unusually low 
latitudes in the southern hemisphere. By Captain James Horsburgh, 
Hydro grapher to the East India Company, F.R.S. 117 
VIII. On the progressive improvements made in the efficiency of steam engines in 
Cornwall; with investigations of the methods best adapted for imparting 
great angular velocities. By Davies Gilbert, Esq. President. . 121 
