Natural History. 183 



the pith of an elder tree at the end of a stick of gum lac, a strong 

 insulating substance, and more portable than glass ; the repulsion 

 from one another was such as to indicate that the atmosphere was 

 in a high state of electricity. Hygrometer I had none. Thermo- 

 meter stood at 45°. — Edin. Phil. Journal, 185. 



2. Description of an Earthquake. — The following minute ac- 

 count of an earthquake is given by Professor Ferrara, of Catania, 

 who seems to have been in the most favourable situation for the 

 observation of such a phenomenon. On Wednesday, the fifth of 

 March, 1823, at twenty-six minutes after five P. M., Sicily suffered 

 a violent shock of an earthquake. I was standing in the large 

 plain before the palace, in a situation where I was enabled to pre- 

 serve that tranquillity of mind necessary for observation. The 

 first shock was indistinct, but tending from below upwards ; the 

 second was undulatory, but more vigorous, as though a new im- 

 pulse had been added to the first, doubling its force ; the third was 

 less strong, but of the same nature ; a new exertion of the force 

 rendered the fourth equal, on the whole, to the second ; the fifth, 

 like the first, had an evident tendency upwards. Their duration 

 was between sixteen and seventeen seconds ; the time was pre- 

 cisely marked by the second's hand of a watch which I had with 

 me. The direction was from north-east to south-west. Many 

 persons who ran towards me from the south-west at the time of 

 this terrible phenomenon, were opposed by the resistance of the 

 earth. The spear of the vane on the top of the new gate connected 

 with the palace, and upon which I fixed my eyes, bowed in that 

 direction, and remained so until the Sabbath, when it fell ; it was 

 inclined to the south-west in an angle of twenty degrees. The 

 waters in the great basin of the botanical garden, as was told me 

 by an eye-witness, were urged up in the same direction by the 

 second shock ; and a palm-tree, thirty feet high, in the same gar- 

 den, was seen to bow its long leafless branches alternately to the 

 north-east and south-west, almost to the ground. The clocks in 

 the observatory which vibrated from north to south, and from east 

 to west, were stopped, because the direction of the shock cut 

 obliquely the plane of their respective vibrations, and the weight 

 of one of them broke its crystal. But two small clocks in my 

 chamber kept their motion, as their vibrations were in the direction 

 of the shock. The mercury in the sismometer preserved in the 

 observatory was put into violent motion, and at the fifth shock it 

 seemed as much agitated as if it were boiling. — Silliman's Journal, 

 ix. 216. 



3. Eodraordinary Rise of the Rio de la Plata. — This river, as is 

 well known, is flooded at certain periods ; and, like the Nile, in- 

 undates and fertilizes the country. The Indians then leave their 



