11 CONTENTS 



Page 

 XI. Observations connected with the History of the Developement of Mag- 

 netism by Rotation. By S. H. Christie, Esq. M. A., F. R. S. of 

 Trinity College, Cambridge, Fellow of the Cambridge Philosophical 

 Society, and of the Royal Military College. In a Letter to the 

 Editor, - - 94 



XII. On the Diamond Mines of Southern India. By H. W. Voysey, 



Esq., - n 07 



XIII. On Magnetic Influence in the Solar Rays. By S. II. Christie, 

 Esq. A. M. F. R. S. of Trinity College, Cambridge, Fellow of the 

 Cambridge Philosophical Society, and of the Royal Military Acade- 

 my. In a Letter to the Editor, - - 104 



XIV. Account of the Expedition under Captain Franklin, and of the Vege- 

 tation of North^ America, in Extracts of Letters from Dr Richardson, 



Mr Drummond, and Mr Douglas. Communicated by Dr Hooker, 107 

 XV, Notice respecting the Mean Temperature of the Equator. By Da- 

 vid Brewster, LL. D. F. R. S. Lond. and Sec. R. S. Edin. 117 

 XVI. On the Specific Gravity of several Minerals. By W. Haidinger, 



Esq. F. R. S. E. (Concluded from Vol. III. p. 246.) - 120 



XVII. Additional Testimony respecting the Sea-Serpent of the American 

 Seas. Communicated by Dr Hooker, - - 126 



XVIII. Description of an Instrument for Extracting and Condensing Air 

 without the assistance of Valves or Stop-cocks. By Andrew Bu- 

 chanan, M. D. Glasgow. In a Letter to the Editor, - 133 



XIX. Observations on the Mean Temperature of the Equatorial Regions. 



By Baron Alexander Humboldt, - - 136 



XX. Notice respecting the hourly Meteorological Observations proposed by 

 the Royal Society of Edinburgh to be made twice every year, on the 

 17th July and 15th January, - - 144 



XXI. On the Deviation of the Magnetic Needle produced by a common 



Electrical Machine. By M. D. Colladon of Geneva, - 149 



XXII. Description of the Volcano of Kirauea, in Hawaii, one of the Sand- 

 wich Islands. By the Reverend William Ellis. With a Plate, 151 

 XX Til. On the Subterranean Sounds heard at Nakous, on the Red Sea, - 153 

 XXIV. Notice respecting the existence of the New Fluid in a large cavity 

 in a specimen of Sapphire. By David Brewster, LL. D. F. R. S. 

 and Sec. R. S. Edin. - - - 155 



XXV. Account of the Carrion Crow, or Vuliur atratus. By Mr John 

 James Audubon, Member of the Lyceum of New York. Commu- 

 nicated by the Author, - - - 156 



XXVI. HISTORY OF MECHANICAL INVENTIONS AND PRO- 

 CESSES IN THE USEFUL ARTS, - - 161 



1 . Account of a New Method of Drawing upon Stone. By M. Laurent, 

 Painter, Paris-. - - - ib. 



2. Experiments on the Discharge of Air by different Orifices. By M. 

 Daubuisson, - - - 162 



3. Method of restoring Wine that has been turned, - 163 



4. Method of preventing, by means of Galvanism, the formation of cal- 

 careous deposits in Lea den Pipes. By M. Dumas, - ib 



5. An Improved method of working Water Wheels. By Mr William 

 Moult. ... 164 



