LISBON. AFTER THE EARTHQUAKE OF 1755, REDUCED FROM AN ENGRAVING, DATED 

 1756, IN THE IMPERIAL LIBRARY AT PARIS. 



EARTHQUAKES AND VOLCANOES. 



CHAPTEE I. 



1. Science tends to the discovery of general laws admits no accidental 

 phenomena. 2. Atmospheric phenomena neither uncertain nor 

 accidental. 3. Physical subterranean agencies. 4. Convulsions inci- 

 dental to the solid shell of the earth. 5. Increase of temperature at 

 increasing depths. 6. Central parts in a state of fusion. 7. Depth 

 at which this liquid state commences. 8. Proportional thickness of 

 the solid shell. 9. Surface of the earth subject to frequent convul- 

 sions from the reaction of the internal fluid matter on the solid shell. 

 10. Geological evidences of this. 11. Physical causes of earth- 

 quakes and volcanoes. 12. Undulations of surface produced by the 

 internal fluid. 13. Their effects on buildings and other objects. 

 14. Vertical and oscillatory motions. 15. Undulations propagated 



LARDNER'S MUSEUM OP SCIENCE. L 145 



No. 40. 



