11 CONTENTS. 



Page 



Art. XI. Remarks on the Influence of the Winds on the Barometer. Com- 

 municated by the Author, - - - - - 241 



XII. On a New Formation of Anhydrous Sulphuric Acid. Observed by C. 

 G. Gmelin, Professor of Chemistry in the University of Tubingen. 

 Communicated by the Author, .... 244 



XIII. Observations on the Temperature of the Sea and the Air, and on the 

 Specific Gravity of Sea- Water, made during a Voyage from St Helena to 

 England in 1820. By John Davy, M. D. K. R. S. Communicated 



by the Author, .,..-. 240 



XIV. Description of Gmelinite, a New Mineral Species. By David Bbew- 

 ster, LL. D. F. R. S. Lond. and Sec. R. S. Fdin. - 2C2 



XV. Description of a New Quicksilver Pump. Invented by Mr Thomas 

 Clark, Edinburgh. Communicated by the Inventor, - - 267 



XVI. Analysis of Helvine. By C. G. Gmelin, Professor of Chemistry in the 

 University of Tubingen. Communicated by the Author, - 2G8 



XVII. Additional Observations on the Natural History and Physical Geo- 

 graphy of the Himalayan Mountains, between the River-Beds of the 

 Jumnah and the Sutluj. By George Govan, M. D. Communicated 



by the Author, ...... 277 



XVIII. Analysis of Diploite, (Breithaupt.) By C. G. Gmelin, Professor of 

 Chemistry in the University of Tubingen. Communicated by the Author, 287 



XIX. Description of a New Double Valve Sluice. Invented by Robert 

 Thom, Esq. Rothesay. Communicated by the Author, - 289 



XX. On the Force exerted by Hydrostatic Pressure in Bramah's Presses ; and 

 on the resisting Power of the Metal, with Rules for computing the thick- 

 ness of the same for different Pressures. By Peter Barlow, Esq. F. H. S. 

 of the Royal Military Academy, Woolwich. Communicated by the Au- 

 thor, ....... 293 



XXI. On the Acoustic Figures produced by the Vibrations communicated 

 through the Air to Elastic Membranes. By M. Felix Savart, 296 



XXII. Analysis of Euchroite. By Edward Turner, M. D. F. R. S. E. 

 &c. Lecturer on Chemistry, and Fellow of the Royal College of Physi- 

 cians, Edinburgh, ...... 301 



XXIII. Description of Fraunhofer's Large Achromatic Telescopes. With a 

 Plate, ....... 305 



XXIV. On the Neptunian Formation of Siliceous Sialactites. By the Rev. 

 John Fleming, D. D. F.R. S. E. Communicated by the Author, 307 



XXV. Notice of the Rev. W. Whewell's General Method of calculating 

 the Angles made by any Planes of Crystals, and the Laws according to 

 which they are formed, ..... 312 



XXVI. On the Methods of Preventing the Accidental Discharge of Fire-Arms. 

 Invented by the Rev. J. Somerville, Minister of Currie. Communi. 

 cated by the Author, ...... 310 



XXVII. On Leslie's Photometer, and its application to determine the relative 

 Intensity of the Sun's Rays, and the Illuminating Powers of Coal and Oil 

 Gas. By William Ritchie, A. M. Rector of the Academy at Tain. 

 Communicated by the Author, ..... 321 



XXVIII. Notice respecting Trona, the native Carbonate of Soda from Fez- 

 zan. By William Haidinger, Esq. F. R. S. Fdin. Communicated 



by the Author, ...... 325 



