been usual before, are always regarded as advantageous to every society. A certain quantity of materials, and the labour of a certain number of workmen, which had before been employed in supporting a more complex and expensive machinery, can afterwards be applied to augment the quantity of work which that or any other machinery is useful only for performing.

The undertaker of some great manufactory who employs a thousand a year in the maintenance of his machinery, if he can reduce this expense to five hundred will naturally employ the other five hundred in purchasing an additional quantity of materials to be wrought up by an additional number of workmen. The quantity of that work, therefore, which his machinery was useful only for performing, will naturally be augmented, and with it all the advantage and conveniency which the society can derive from that work.