Injluence of Climate on Cultivation. 
167 
the characteristics of a later variety. The individual plants, 
having more space to expand their roots in, form correspondingly 
large stems. The increased scale on which the plant grows 
enables it to maintain a larger absorbent surface of leaf. 
The seeding tendency of each plant is retarded by the larger 
supply of food furnished. Its lateness also causes its growth to 
take place to a greater extent during the warmer season, when the 
absorbing powers of the leaves are greatest. These elements no 
doubt contribute to the success of growing wheat at Lois Weedon 
with so little expenditure of manure ; and whatever may be the 
other elements of success, these cannot be left out of view. 
The practical effects of thick and thin seeding have been 
philosopliically treated in the farming essays of Mr. Mechi and 
Mr. Hewit Davis. Thick seeding, by limiting the amount of 
moisture and manure to each plant, hastens its flowering pro- 
cesses. It need hardly be again observed that a deficiency of 
moisture and a deficiency of manure are similar in their effects 
upon plants : the want of moisture renders the presence of 
manure of little avail. Both, therefore, favour the early maturity 
of plants, which is well known to accompany thick seeding. 
Thin seeding, on the contrary, whatever may be its other 
disadvantages by limiting the number of plants and extending 
their growth over a longer period, is a means of economising 
both moisture and manure. 
Temperature, humidity, manuring, and the physical properties 
of soils derive a considerable amount of fresh interest on viewing 
their effects on the growth of the wheat plant when sown in 
spring. A low temperature during the early stages of the 
common and finer varieties of wheat seems quite as natural to its 
productive powers as a high temperature to ripen it. When 
wheat, as already stated, is sown in warm climates or in summer, 
it exhibits little or no tendency to flower. In North America, where 
the heat sets in so suddenly after the cold of winter, none of the 
common varieties are sown in spring, as few of the plants will in 
that case produce seed that summer. The same circumstance is 
observed in the soutli of France ; and even in the south-eastern 
counties of England, when the time of sowing is somewhat delayed, 
the plant puts forth a profusion of stems and leaves, and the high 
temperature, instead of pushing the plant rapidly into ear, at that 
stage of its growth, has a precisely contrary tendency. It no doubt 
has such an effect on a plant sown in the end of February or 
beginning of March, for the cold at that season fully developes 
its seeding tendencies. The cold nights and warm days, which 
are the characteristics of the climate of the eastern counties at 
that season, hasten it on so much that a full plant is difficult to 
obtain, even with a liberal allowance of manure. Hence these 
