Unions of comparatively unskilled workers, who are never free from the competition of unemployed, and who cannot undertake permanently to buy off all competitors ready to underbid, endeavour to limit the numbers of their members, and to prevent outsiders from effectively competing with them in the labour market, in order that by restricting the supply of labour, they may prevent a fall of wages.

The importance of these movements for us consists in their firm but tacit recognition of the fact, that an excessive supply of unskilled labour lies at the root of the industrial disease of "sweating." Sec.2.The Contributing Causes of excessive Supply .-- The last two chapters have dealt with the principal large industrial movements which bear on this supply of excessive low-skilled labour; but to make the question clear, it will be well to enumerate the various contributing causes.
[Greek: a].

The influx of rural population into the towns constantly swells the supply of raw unskilled labour.

The better quality of this agricultural labour, as we saw, does not continue to form part of this glut, but rises into more skilled and higher paid strata of labour.

The worse quality forms a permanent addition to the mass of inefficient labour competing for bare subsistence wages.
[Greek: b].