The produce of all great manufactures for distant sale must necessarily depend, not so much upon the dearness or cheapness of the seasons in the countries where they are carried on, as upon the circumstances which affect the demand in the countries where they are consumed; upon peace or war, upon the prosperity or declension of other rival manufactures and upon the good or bad humour of their principal customers. A great part of the extraordinary work, besides, which is probably done in cheap years, never enters the public registers of manufactures. The men-servants, who leave their masters, become independent labourers. The women return to their parents, and commonly spin, in order to make clothes for themselves and their families. Even the independent workmen do not always work for public sale, but are employed by some of their neighbours in manufactures for family use. The produce of their labour, therefore, frequently makes no figure in those public registers, of which the records are sometimes published with so much parade, and from which our merchants and manufacturers would often vainly pretend to announce the prosperity or declension of the greatest empires.
Though the variations in the price of labour not only do not always correspond with those in the price of provisions, but are frequently quite opposite, we must not, upon this account, imagine that the price of provisions has no influence upon that of labour. The money price of labour is necessarily regulated by two circumstances; the demand for labour, and the price of the necessaries and conveniencies of life. The demand for labour, according as it happens to be increasing, stationary, or declining, or to require an increasing, stationary, or declining population, determines the quantities of the necessaries and conveniencies of life which must be given to the labourer; and the money price of labour is determined by what is requisite for purchasing this quantity. Though the money price of labour, therefore, is sometimes high where the price of provisions is low, it would be still higher, the demand continuing the same, if the price of provisions was high.