CONTENTS. 
XI. Some curious facts respecting the Walrus and Seal, discovered 
by the examination of specimens brought to England by the 
different ships lately returned from the Polar Circle. By Sir 
Everard Home, Bart. V. P. R. S. In a Letter addressed to 
Sir Humphry Davy, Bart. Pres. R. S. - p. 233 
XII. Additional Experiments and Observations on the Appli- 
cation of Electrical Combinations to the Preservation of the 
Copper Sheathing of Ships, and to other purposes. By Sir 
Humphry Davy, Baft. Pres. R. S. - - - 242 
XIII. On the Apparent Direction of Eyes in a Portrait. By 
William Hyde Wollaston, M. D. and V. P. R. S. 247 
XIV. Farther particulars of a case of Pneumato- thorax. By 
John Davy, M. D. F.R.S. - - - 257 
XV. On the action of finely divided Platinum on Gaseous Mix- 
tures, and its Application to their Analysis. By W illiam 
Henry, M. D. F. R. S. - - - 2 66 
XVI. A Comparison of Barometrical Measurement, with the 
Trigonometrical Determination of a Height at Spitzbergen. 
By Captain Edward Sabine, of the Royal Regiment of 
Artillery, F. R. S. - - - - - 290 
XVII. Experimental Inquiries relative to the distribution and 
changes of the Magnetic Intensity in ships of war. By George 
Harvey, Esq. Communicated by John Barrow, Esq. F. R. S. 
310 
XVIII. Experiments on the elasticity and strength of hard and 
soft steel. In a Letter to Thomas Young, M. D. For. Sec. 
R.S. By Mr. Thomas Tredgold, Civil Engineer. Com- 
municated by Dr. Young. - 354 
XIX. A short Account of some Observations made with Chrono- 
meters, in two Expeditions sent out by the Admiralty , at the 
