CONTENTS. ni 



PAGE 



XVII. On the Determination of Copper and Nickel in quan- 

 titative analysis. By David Forbes, F.G.S., Ass. 

 Inst. C.E., Espedalen, Norway. Communicated by 

 the Author, . . . . .131 



XVIII. On the Origin of Slaty Cleavage. By Henry Clif- 

 ton Sorby, F.G.S. Communicated by the Author, 137 



XIX. On the Determination of the Figure and Dimensions 



of the Globe. By Colonel Sabine, . . 148 



XX. On the Distribution of Heat at the Surface of the 



Sun. By Professor Secchi, . . .150 



XXI. On the Mean Density of the Superficial Crust of the 



Earth By M. Plana, • . .152 



XXII. Lieutenant Maury's Plan for Improving Navigation ; 

 with Remarks on the Advantages arising from the 

 Pursuit of Abstract Science. Extracted from Lord 

 Wrottesley's Speech in the House of Lords, on 26th 

 April 1853, . . . . .154 



XXIII. Observations on the Arctic Relief Expeditions. By 



Augustus Petermann, Esq., . . .159 



XXIV. A Description of Lunar Volcanoes. By Professor 

 Secchi, ..... 161 



XXV. Livingston's Researches in South Africa, . 164 



XXVI. On the Crystalline Form of the Globe. By M. de 



Hauslab, . . . . .165 



XXVII. On the Classification of Mammalia. By Charles 



Girard, of Washington, . . .167 



