June 27, 1859.] KING'S TRAVELS IN SIAM AND CAMBODIA. 367 



place is generated which is 1200 feet deep, and which in consequence is much 

 warmer than the spot which existed at the same locahty before ; but also that, 

 on account of the formation of the erosion, a current of heated air is going up 

 as through a funnel, which acts most effectually in reducing the size of the 

 glacier, and which gradually increases as the erosion extends. Another curious 

 fact, which, we think, finds its explanation by the erosion, is the absence of 

 waterfalls in the mountain systems of High Asia, and more especially in the 

 Himalayas, where this want of waterfalls often has been mentioned without 

 any attempt at explanation. The opinion about this remarkable want of 

 waterfalls which we allow ourselves to present is this : The lateral rivers, 

 during the rainy season, have such an increase of water that they act nearly 

 as powerfully as the large rivers do, since at the same time they have a much 

 steeper descent. The consequence is that generally the large and small rivers 

 unite at about the same angle of inclination. Consequently waterfalls which 

 formerly existed, and of which traces are yet seen, have been entirely elimi- 

 nated from the Himalayas. 



Another consequence of the erosion is the gradual drainage of fresh water 

 lakes, or their conversion into salt water lakes. It is very characteristic for the 

 Himalayas, and in this respect they differ essentially from most other mountain 

 systems in the world, that hardly any fresh-water lakes now occur. The only 

 few lakes of any considerable extent which have been made known by Captain 

 Strachey, Captain Speke, and Major Cunningham, as well as those we visited 

 besides, are all salt water. But the explanation we think we must give of 

 this phenomenon is different from the explanation formerly given. Some have 

 thought that a raising of the country might have caused a general drainage. 

 We think that supposition rather improbable, from the recent strata round 

 these salt lakes being all horizontal, and the outlets of these salt lakes being 

 in a .different direction in reference to the horizon. If any raising of the 

 country had effected the drainage of the salt lakes, the effect would have been 

 a perfectly different one, according to the position the outlet of these lakes had 

 in reference to the points of the horizon, a modification which is nowhere met 

 with. 



The Tso mo Ri ri and the Tso mo Gnalari, the two great salt lakes of Eupchu 

 and Pankong, of which drawings are presented, happen to be a good example 

 of two large lakes, being about equally salt, with differently directed former 

 outlets, and with quite horizontal banks of detritus and of watermarks along 

 their circumferences. The gradual progress of the erosion of the valleys seems 

 to us to be also the chief cause of the gradual transformation of freshwater 

 lakes into saltwater lakes in Tibet. 



By this progressive excavation thousands of square miles, still marked as 

 former lakes by the form of the surface, have been emptied, and the consequence 

 is that the local evaporation could no more keep the equilibrium with the pre- 

 cipitation ; in consequence the lakes, of which parts remained undrained on 

 account of their greater depth, now gradually became more and more salt. I 

 could add still many observations about the various characteristic features of 

 the physical geography of the tropical and high land and glacial regions, which 

 we have tried to represent in our drawings, amounting, as the catalogue pre- 

 sented shows, to 700 ; but 1 conclude with repeating my apologies for having 

 already passed the hour allowed to discussion. 



Sir Roderick Murchison. — A very great subject which has been brought 

 before you by my friend Mr. Hermann Schlagintwcit— one which would lead 

 us into the consideration of the physical geography of the Himalayan and 

 Karakorum chains, and even beyond the latter across the Kuen Lun — subjects 

 too vast to be entered upon at this hour of the night. The observations which 

 my friend has just addressed to you respecting the lakes, drainage, and the 

 ancient configuration of this country, are obviously matters of such magnitude, 



