LAKES. 



321 



attended with great disturbance on the lake, a storm will produce much less effect. 

 These circumstances have some connection with the physical condition of the district a 

 focus of earthquakes but the links between the two are unknown to us; another evi- 

 dence, that, in the physics of the earth, there is much yet beyond the reach of our philo- 

 sophy. A small expanse of water near Beja in Portugal is said to announce a storm by 

 its commotions ; but, in general, the movements of lakes are confined to those produced 

 by their own river-currents, and the action of the external atmosphere. Winds produce 

 an effect upon their surface, regulated by the extent exposed to their influence, and the 

 character of the surrounding shores. The heavy autumnal gales that sweep over the 

 ample volume of Lake Superior, rouse it into tempest, and raise its waters several feet 

 upon the opposite beach ; and small mountain-lakes are often violently agitated by the 

 winds, which rush with greater power through the openings in their boundary, from the 

 interruption which its walls present to their course. 



Lake Saratoga. 



The smaller lakes of America, whose wild and solitary shores attract the tourist, of which 

 the above view of Lake Saratoga affords a specimen, have some singular physical pecu- 

 liarities. One of the early explorers of its northern regions, Sir Alexander Mackenzie, 

 was the first to notice the attractive power of the mud at the bottom, which is some- 

 times so great, that boats can with diificulty proceed along the surface. This extra- 

 ordinary fact is thus stated : " At the portage or carrying place of Martres, on Rose 

 Lake, the water is only three or four feet deep, and the bottom is muddy. I have 

 often plunged into it a pole twelve feet long, with as much ease as if I merely 

 plunged it into the water. Nevertheless, this mud has a sort of magical effect upon the 

 boats, which is such that the paddles can with difficulty urge them on. This effect 

 is not perceptible on the south side of the lake, where the water is deep, but is more 

 and more sensible as you approach the opposite shore. I have been assured that loaded 



