vi . MOUNTAINS 233 
well as the rivers issuing from them, are a 
beautiful rich blue. 
“Ts it not probable that this action of 
finely-divided matter may have some influ- 
ence on the colour of some of the Swiss lakes 
—as that of Geneva for example? This lake 
is simply an expansion of the river Rhone, 
which rushes from the end of the Rhone 
glacier, as the Arveiron does from the end of 
the Mer de Glace. Numerous other streams 
jom the Rhone right and left during its 
downward course; and these feeders, being 
almost wholly derived from glaciers, join the 
Rhone charged with the finer matter which 
these in their motion have ground from the 
rocks over which they have passed. But the 
glaciers must grind the mass beneath them 
to particles of all sizes, and I cannot help 
thinking that the finest of them must remain 
suspended in the lake throughout its entire 
length. Faraday has shown that a precipi- 
tate of gold may require months to sink to 
the bottom of a bottle not more than five 
inches high, and in all probability it would 
require ages of calm subsidence to bring all 
