CONTENTS. 



Page 

 Art. I. Historical Eloge of Joseph Fourier. By M. Arago, 

 Perpetual Secretary to the Academy of Sciences 

 of France, . . . . . 1 



II. On the Natural History of Volcanos and Earth- 

 quakes. By Dr Gustav Bischof, Professor of 

 Chemistry in the University of Bonn. Commu- 

 nicated by thc; Author, . . . 25 



1. Are Volcanic phenomena capable of a satisfactory 

 explanation from the increase of temperature to- 

 wards the centre of the Earth, or can Chemical 

 processes be admitted with greater probability to ^' 



be the cause of Volcanic action ? . . . 25 5 



1. The hypothesis, which ascribes Volcanic 



phenomena to intense Chemical action, 

 shewn to be untenable, ... 26 



2. The hypothesis which supposes the Tem- 



perature of the Earth gradually to increase 

 towards the centre, to a red and white 

 heat, explains in a satisfactory manner 

 (according to the present state of science) 

 Volcanic phenomena as well as Earth- 

 quakes, 05 



III. On Thunder and Lightning. By M. Arago, 81 



1. Of Lightning, . . ... . .82 



2. Sheet Lightning, 86 



3. Concerning Ordinary Thimder, — the time between it 



and the Lightning, — Thunder Claps, — the extreme 

 distance at which it may be heard, — the Thunder 

 of serene weather, — and of the Length of the Light- 

 ning's Hash, 91 



