VEGETABLE PRODUCTIONS OF NORWAY. 241 
eventually assumes the same green appearance, and 
thus continues till it enters the Midsen at Lillehammer, 
in fact, colouring the water of the lake for some little 
distance below its debouchure. The Otta Ely rises in 
the glaciers on the Lang Field, and is at. first of a 
milky appearance, and is opaque; but when the silicious 
matter with which it is laden is deposited, 1t assumes a 
bright sea-green colour, and becomes transparent. 
The ultimate transparency of the water is even more 
remarkable than is its assuming a green colour. 
In the upper parts of the Orinoco a similar phe- 
nomenon was observed by Humboldt, where the water 
in several of the small tributary streams was trans- 
parent and bright yellow when examined in a glass, 
whilst in the bed of the river it assumed a dark coffee- 
brown colour, and appeared quite black in the shade. 
Something similar to this has also been observed 
in parts of the Amoor, and of the Jumna. 
Norway abounds, too, in lakes, mostly of an in- 
considerable size, and often lying at great altitudes. 
As is usually the case with mountain lakes, they are of 
great depth, and their waters are intensely cold and 
very transparent. Generally speaking, their width is 
inconsiderable. 
~The Midsen, which is the largest, and is about 70 
miles long, is 400 feet above the sea. From several of 
these, rivers take their rise, and run in opposite 
R 
