CHANGES OF QUANTITY. 229 



In England it is in fogs and fens in the winter, and 

 in the crops on the fields, and the leaves, flowers, 

 and fruits of other annual and deciduous vegetables, 

 in the summer. In climates farther to the north, it 

 is during winter piled up in snow and ice : and in 

 summer it is either at work hi the more scanty 

 vegetation, or it has ebbed away to the ocean in 

 the spring " freshes" and flools. The action of 

 gravitation distributes it equally in the ocean ; and 

 when it rises in vapour, the action of heat disperses 

 it in the atmosphere. 



What these causes may from time to time pro- 

 duce we cannot calculate ; but within a very long 

 period of duration one as long at least as we have 

 any thing like authentic information, it does not 

 appear that the great collected quantity has varied 

 much. Now, according to the estimates, which on 

 such a subject must be vague, if the solid parts of 

 the earth those parts that we have denominated 

 land in distinction from water were in the form 

 of a regular spheroid, the form which gravity and 

 the revolution and rotation of the earth (the only 

 external causes that we know that could act upon 

 principles that we understand in moulding the earth 

 into its form), the water would cover it with a 

 crust (if the term may be used), or shell of water, 

 something about two miles in thickness. That 

 would give a pressure of more than two tuns on 

 every square inch of the solid nucleus, exclusive of 

 the pressure of the atmosphere, or a pressure equal 

 to the weight of the whole navy of Great Britain 

 on a surface equal to the floor of an ordinary-sized 

 room. 



When we reflect upon that immense resistance 

 of pressure which the internal powers of the earth 

 that elevated the mountains had to overcome, we 

 may cease to wonder at the results that have been 

 produced ; nor need we be in the least astonished 

 when we go to mountainous countries, and find 



