Iiifluence of Climate on Cultivation. 
485 
crop furnishes remarkable illustrations of its greater or less de- 
pendence on the soil for a supply of nitrogen for its growth, 
according to the climatic conditions under which it may be 
grown. If this principle be overlooked, it is in vain to think 
of arriving at accurate ideas respecting the relative exhausting- 
qualities of plants. 
Flax has long been cultivated by the small farmers of the 
northern parts of Ireland, and is extensively grown there at the 
present day. Arthur Young, in his ' Tour in Ireland, in 1776-7-8,' 
writes : — " There is a notion common in the north of Ireland, which 
I suppose must be very prejudicial to the quality as well as the 
quantity produced : it is, that rich land will not do for it, and 
that the soil sliould be pretty much exhausted by repeated crops 
of oats, in order to reduce it to a proper state for Hax." This 
notion was, no doubt, very erroneous, but it is to be traced to 
the particular practices which were followed, and formed a part 
of a system not inconsistent in itself — all the other crops, chiefly 
oats and barley, were invariably sown late, as the land was in 
poor condition. Flax, when sown early on land exhausted, is 
exceedingly susceptible of frosts in spring, and will seldom pro- 
duce other than a poor return ; but, on the other hand, when 
sown late, temperature being to some extent an equivalent for ni- 
trogenous manure, tolerable crops are obtained, although the land 
is considerably exhausted. When sown late on rich soil, the 
plant rashes rapidly forward, and weak straw liable to fall down 
is the result. Under these conditions we can readily believe that 
rich land is prejudicial to the grov.'th of flax. The fact, however, 
of a crop, like flax, growing even moderately well on land which 
is in a poor or exhausted state, implies that it has great powers 
of relying upon the atmosphere for carbonic acid and ammonia. 
It is difficult to reconcile its exhausting properties with its capa- 
bility of growing on land whose fertility has been reduced by several 
successive crops of oats or barley. So far as the soil was concerned, 
under the rotations pursued when Young made his tour in Ireland, 
there Avas not mucli in it to exhaust when it was considered fit 
for a crop of flax. We can only attribute the opinion of the ex- 
hausting qualities of flax to its habit of growing freely when 
sown during the warmer period of the year, even on poor soil, 
and thus using up the remains of fertility. 
The practices followed in the cultivation of this plant in other 
countries support these views in a remarkable degree. In Belgium 
the finest crops of flax, in point of quantity and quality, are 
raised. There it receives liberal dressings of manure. Indeed, 
the exhausting qualities of the plant may be said to be courted, 
inasmuch as it may either be grown with much or little manure. 
The farmers have clearly recognised the principle, that an in- 
