of the last Half of the Year 1817. 1 97 



nourishment, they descended all at once upon some field, sojourned 

 there for some hours, and afterwards resumed their course. At 

 night the air was quite crowded with these insects. 



On the 2d of July the mountain of Hansruck in Upper Au- 

 stria disappeared and gave place to a lake. Tiiis mountain was 

 of great elevation, and gave its name to the country around. 

 During the preceding month there had been various phaenomena, 

 which augured some ruinous event : — subterraneous noises — 

 slight explosions on the exterior, &c. they had disqu'eted the 

 people of the country greatly, and seemed as if designed to tore- 

 warn them of their danger. 



On the 24th of the same month, the very opposite of this 

 phsenomenon occurred in Italy. An astonishing noise was heard 

 in the territory of Ferentino; after which the waters of the lake 

 of Porciano suddenly disappeared, and left their ancient bed quite 

 dry. Eastward of the lake, at the foot of a neighbouring moun- 

 tain, tlv^y discovered an enorinous chasm, produced by some vio- 

 lent commotion, down which the waters had precipitated them- 

 selves into certain subterranean caverns which now serve as their 

 receptacle. — The Romans prevented accidents of this sort by 

 rheir famous canals of outlet, as we see in the lake of Albano ; 

 but the modern inhabitants of the volcanic country of Rome 

 have not the same foresight. 



In the month of August, another displacement, owing without 

 doubt to the subterraneous conflagration of a bed of coal or sul- 

 phurous matters, happened near Salzbourg in Bavaria, on the 

 borders of the Salza. A space of ground, of the extent of about 

 fifteen acres, sunk down, and from the chasm left, flames con- 

 tinued to issue for four days afterwards, exhaling a strong sul- 

 phurous odour. 



On the 12th of May preceding, the bailiwick of Rattenberg 

 presented a spectacle still more frightful. A whole mountain 

 tumbled down, and transformed into a desert a very fertile and 

 well-peopled valley. The cause to which this has been attri- 

 buted was the enormous quantity of snow which fell in the Tyrol, 

 in February, March, and April, and which a sudden change of 

 temperature and abundant hot rains had precipitately melted. 



On the 5th July, at one o'clock in the nhorning, the waters of 

 the sea suddenly withdrew from the port of Marseilles, and left it 

 for some moments quite dry; but soon after returned, and spread 

 as far even as the city. The same phaenomenoq was observed 

 with still more remarkable characters on the 27th of June 1812, 

 and occurred also in 1775, at the time pf the famous earthquake 

 of Lisbon. 



The atmospheric whirlpools, which are attributed to a displace- 

 ment of heated air, and by the action of which it is easy to ex- 

 N 3 plain 



