57? Cultivation of Plants. 
the composition of the soil and its deficienvy in certain de- 
sirable constituents. Inorganic, or purely artificial mineral 
manures, are seldom needed save where the crops are taken off 
the ground, in which case it becomes necessary to replace some 
substauces taken from the soil. The principal thing to bear in 
mind in manuring is the fitness of the manure used for the soil 
it is wished to improve. 
Vegetation is soon scorched up where the soil is sandy and 
shallow ; but where there is a good depth of sandy loam, the 
quantity of water is more uniform throughout the year; 
neither an excess in winter, nor relatively so great a defi- 
ciency during a dry summer. Much may be done by deep 
and thorough tillage and frequent breaking of the surface 
to render heavy soils more productive, because the water 
will thereby be drained from the surface when there is an 
excess, and attracted towards it when there is a deficiency. 
The greater the amount of evaporation the lower the tempera- 
ture; thus natural or artificial drainage affects the soil in 
two ways by relieving it of its superabundant moisture. It is 
important to bear in mind that a light soil, although exposed 
to greater extremes of temperature at and near its surface, 
maintains a higher temperature below a certain depth, and 
also that there is less evaporation from its surface. These two 
conditions materially modify the effects of frost, and are of 
as much importance to the practical horticulturist as the 
strictly climatal peculiarities of a district. 
§ +. CuLrunan Directions. 
1. General Remarks. 
Gardening operations are so multifarious, and the circum- 
stances under which they are performed are so varied, that 
many large books have been written treating of them in detail, 
for the instruction of gardeners and amateurs. Perhaps the 
greatest. fault of all or nearly all works of this description is 
their size, and the length at which the simplest matters are 
treated—usually with such minuteness of detail as to bewilder 
and discourage a beginner and cause him to throw aside a 
work that might in many instances be of great service to him. 
It is idle to attempt to teach practical gardening or any other 
branch of industry from the beginning by written instructions. 
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