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places it may be very far down. But the nearer it 
is, the damper and more unhealthy becomes the 
top-soil, because the water rises through it. 
8. As a rule, the soil that has least dampness is 
a gravelly one, if it does not receive the drainage 
from higher land. 
9. Peaty soils, and those that have been formed 
by the mud brought down by rivers, are usually 
very damp. In them there is much decaying animal 
and vegetable matter, which gives off gases that 
are bad for us. It is in the early morning, or 
towards evening, that the poisonous vapours from 
such soils are most to be feared. The sun causes 
them to rise towards the sky by day; but in the 
cold of night or morning they float around us, and 
are likely to bring on illness. 
10. In some countries the subsoil is drained, where 
needful, by laying in pipes to carry off some of the 
water. This is a very good plan; and, if it were 
carried out in Jamaica, most likely there would be 
fewer cases of fever. 
n. We must bear in mind that, when the water 
in the subsoil rises, the gases that are in the soil 
above it are forced out. From this cause a site may 
be unhealthy even where the top-soil is mostly dry. 
In fact, some of the gravelly banks of the Jamaica 
rivers are known to be malarious. 
