178 Scientific Intelligence, — Meteorology. 



was compelled, with extreme expense and inconvenience, to pull 

 down the whole inner walls, and build them afresh in a more 

 secure manner. From the same cause, a new magazine which 

 government directed to be built, with an arched roof of brick- 

 work, was, when complete, found so very unsafe, that it was ne- 

 cessary to demolish it entirely, and rebuild it on a new plan, 

 with a roof of tiles. In such a soil, it will easily be concluded 

 that swamps and lagoons prevail very much, of course, mostly 

 during the rains, and till the sun gathers power in the hot 

 weather ; and, in fact, what has been above so much insisted on, 

 as to the two contrary aspects of the country with respect tg vege- 

 tation, may, by a conversion of terms, be equally applied to the 

 water on its surface. In the cold and dry weather it is compa- 

 ratively scanty, in the rains it is superabundant ; and as the 

 rivers in this district are frequently found to change their situa- 

 tions, so, through a long course of time, it has resulted that 

 hollow beds, being deserted by their streams, become transform- 

 ed into what, during the rains, assume the appearance of exten- 

 sive lakes, but in dry weather degenerate into mere muddy 

 swamps, overgrown with a profusion of rank aquatic vegetations, 

 particularly the gigantic leaves of the lotus, and swarming with 

 every tribe of loathsome cold-blooded animals. Some of these 

 lakes, during the height of the rains, communicate with their 

 original streams, and thus undergo a temporary purification ; 

 but others receive no fresh supply except from the clouds, and 

 of course their condition is by much the worse. Some of the 

 conversions of a river-bed into a lake, have occurred in the me- 

 mory of the present inhabitants, or at least within one descent 

 from their ancestors. — Tytler, on the Climate of' Mullye^ in 

 Trans. Med. c§* Phys. Soc. of Calcutta., vol. iv. 



GEOLOGY. 



5. Heights of Table Lands. 



Toises above the sea. 

 The table land of Iran in Persia, - - 650 



Table land in which Moscow is 

 The plain of Lombard^, 

 Table land of Swabia, 



Auvergne, 



— Schweitz, 



' Bavaria, 



■ Spain, 



situated, - 67 



80 

 150 

 174 

 220 

 260 

 350 



