57 2 Cultivation of Plants. 



the composition of the soil and its deficiency 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 

 substances 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 daring 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. 



4. CULTURAL 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 frorn the beginning by written instructions. 



