labour, in proportion to its quantity, comes always too cheap to market to afford anything but the most scanty subsistence to the labourers.

Disagreeableness and disgrace affect the profits of stock in the same manner as the wages of labour. The keeper of an inn or tavern, who is never master of his own house, and who is exposed to the brutality of every drunkard, exercises neither a very agreeable nor a very creditable business. But there is scarce any common trade in which a small stock yields so great a profit.

Secondly, the wages of labour vary with the easiness and cheapness, or the difficulty and expense of learning the business.

When any expensive machine is erected, the extraordinary work to be performed by it before it is worn out, it must be