250 FLAX CULTIVATION IN BELGIUM. 
the largest extent in the sandy soil of Flanders, it is also 
produced in some of the clay districts, and also on the strong 
lands of the Polders. More consideration is to be given to 
the climatic conditions ; the period of vegetation of the flax 
plant being relatively short, its cultivation is centred in 
localities where the fluctuations in temperature are least 
marked, and where the operations of sowing can consequently 
be carried out in a short period. The question of rainfall does 
not appear to be of equal importance, since it varies consider- 
ably in the flax growing districts ; on the other hand, the crop 
is grown largely along the courses of certain rivers, notably 
the Lys, the waters of which are particularly suitable for 
retting. Apart from these natural conditions some account 
must be taken of the economic conditions, such as the 
abundance of labour; for instance, it is observed that in the 
districts where flax is chiefly grown the density of population 
considerably exceeds that of the remaining districts of 
Belgium. 
[Recensement Général de 1895. Parte analytique. | 

