CONTENTS. vii 



AUGUST, 1808. 



Engravings of the following Objects: 1. Mr. Wright's Artificial Horizon: S. 

 Mr, Daniel's Life Preserver frem Shipwreck : 3. Lieut, Beirs Method of sav- 

 ing Persons from stranded Ships. 



I. Observation? on the crystallized Substances included in Lavas. By G. A. 

 Deluc ------ 241 



U. Experiments on Molybdena, By Christian Frederic Bucholz 25S 



nf. On the native Gold Dust found in the Hills in the Environs of the Com- 

 mune of St. George's, in the Department of the Doire. By Mr. Giulio, 

 Prefect of the Department of the Sesia - - _ 266 



IV. Calculation of the direct Attraction of a Spheroid, and Demonstration of 

 Clairaut's Theorem. By a Correspondent - - 273. 



V. Keply to Professor Vince's Ultimatum. By a Correspondent 275~ 



VI. Question respecting the Ignition of Tinder by compressed Air. In a Let- 

 ter from a Correspondent - - - - 271 



VII. Description of a portable artificial Horizon for taking Altitudes at Sea or 

 I^nd, by Mr. Wright. In a Letter from the Inventor - 279 



VIII. Description of an Apparatus to secure Persons from sinking in Water, or 

 to act as a Life-preserver when shipv/recked, with Instances of its Utility 

 By Mr. F. C. Daniel, of Wapping - - - 2« i 



iX. Account of Experiments made by Lieutenant John Bell, of the Royal Ar- 

 tillery, to ascertain the Practicability of throwing a Line to the Shore frem a 

 Vessel stranded - - - . . 28S 



X. The Bakerian Lecture, on some new Phenomena of Chemical Changes pro- 

 duced by Electricity, particularly the Decomposition of the fixed Alkalis, 

 and the Exhibition of the new Substances which constitute their Bases; and 

 on the general Nature of Alkaline Bodies. By Humphry Davy, Esq. Sec. 

 R. S. M. R. I. A. - - - - - 290 



XI. Remarks on Iron Spar. By Mr. Bergman - - 314 



XII. Analysis of a Urinary Calculus. By Professor Wurzer - 317 

 Scientific News - . . . , 218 

 Meteorological Journal . . . . 320 



SUPPLEMENT, 



