The unproductive class, however, is not only useful, but greatly useful, to the other two classes. By means of the industry of merchants, artificers, and manufacturers, the proprietors and cultivators can purchase both the foreign goods and the manufactured produce of their own country, which they have occasion for, with the produce of a much smaller quantity of their own labour, than what they would be obliged to employ, if they were to attempt, in an awkward and unskilful manner, either to import the one, or to make the other, for their own use. By means of the unproductive class, the cultivators are delivered from many cares, which would otherwise distract their attention from the cultivation of land. The superiority of produce, which in consequence of this undivided attention, they are enabled to raise, is fully sufficient to pay the whole expense which the maintenance and employment of the unproductive class costs either the proprietors or themselves. The industry of merchants, artificers, and manufacturers, though in its own nature altogether unproductive, yet contributes in this manner indirectly to increase the produce of the land. It increases the productive powers of productive labour, by leaving it at liberty to confine itself to its proper employment, the cultivation of land; and the plough goes frequently the easier and the better, by means of the labour of the man whose business is most remote from the plough.