MINERAL RESOURCES OF DEVON AND CORNWALL. 197 
Of its many valuable properties its most remarkable, and probably 
its most valuable, is that of mobility. It can be readily changed 
from the solid to the liquid, from the liquid to the gaseous, and 
from the gaseous back again to the solid, and consequently can be 
transferred from one locality to another with the greatest ease. 
Its principal source of supply is the ocean. The sun is our 
earth’s great steam-engine, always at work pumping up water from 
the ocean, transferring it to the land, depositing it in store-houses 
on lofty mountains 5,000 to 25,000 feet high. The mountains act 
as the surface condensers of steam-engines in restoring water from 
the invisible form in the rarified atmosphere, approaching consider- 
ably towards a vacuum. Precipitated in the state of snow, it is 
further condensed and solidified into the form of ice in glaciers, in 
which condition it is preserved until the increased heat of the 
summer’s sun unlocks these mountain storehouses. In Devon and 
Cornwall the mountain ranges are comparatively insignificant. They 
do not reach very high into the atmosphere; nevertheless, from 
their proximity to the sea, and their peninsular arrangement, they 
become the agents of supply of much more than has yet been fully 
utilized. On the extensive moors of Dartmoor and Exmoor there 
are vast spongy coverings of peat which serve instead of glaciers to 
store up water in vast quantities, sufficient for the constant supply 
of many rivers. For want of proper consideration, this mineral has 
not yet been utilized to anything like the extent to which it may 
be applied. Very often we hear great complaints of the incon- 
veniences occasioned by the excessive supply of this valuable 
material; nevertheless, but little has yet been done to properly utilize 
that which is obtainable. In order to understand this, we shall do 
well to devote a few minutes to the consideration of the purposes 
for which water is required. They may be considered under two 
heads ; viz., mechanical and chemical. 
Taking Nature as our teacher, we may apply the mechanical 
properties of water for the purpose of disintegrating masses, as is 
done extensively in the two counties, as we shall presently have 
occasion for illustration in noticing the methods of obtaining and 
preparing china clay ; but very much yet remains to be done to 
obtain the full value of the supplies of water obtainable for such 
purposes. To fully appreciate this, we should note what is being ac- 
complished elsewhere. In California, for instance, in ‘‘hydraulicing,” 
or hydraulic operations, many joint stock companies are in opera- 
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