Sculpturing of the Mountains. 813 
of the underground rocks. This invisible material 
finds its way, as the springs do, to the rivers, and so, 
finally, is brought into that great reservoir, the sea. 
Rain and river-water also dissolve a certain amount of 
mineral matter from rocks lying on the surface of the 
earth. Now, the material which is most easily 
dissolved is carbonate of lime. Hence, if you take a 
small quantity of spring or river-water, and boil it 
until the whole is evaporated, you will find that it 
leaves behind a certain amount of deposit. This, when 
analysed by the chemist, proves to be chiefly carbonate 
of lime ; but it also contains minute quantities of other 
minerals, such as common salt, potash, soda, oxide of 
iron, and silica. All these and other minerals are 
found to be present in sea-water, 
“The waters of some of the great rivers of the 
world have been carefully examined at different times, 
in order to form some idea of the amount of solid 
matter which they contain, both dissolved and sus- 
pended ; and the results are extremely important and 
interesting, for they enable us to form definite con- 
clusions with regard to their capacity for transport. 
This subject has been investigated with great skill by 
eminent men of science. The problem is a very com- 
plicated one; but it is easy to see that if we know 
roughly the number of gallons of water annually 
discharged into the sea by a big river, and the average 
amount of solid matter contained in such a gallon of 
water, we have the means of calculating, by a simple 
process of multiplication, the amount of solid matter 
