All the labor [not engaged in preparing materials] tends constantly and strongly toward diminution, as the amount of production increases. Manufactures are vastly more susceptible than agriculture of mechanical improvements and contrivances for saving labor. In manufactures, accordingly, the causes tending to increase the productiveness of industry preponderate greatly over the one cause which tends to diminish it; and the increase of production, called forth by the progress of society, takes place, not at an increasing, but at a continually diminishing proportional cost. This fact has manifested itself in the progressive fall of the prices and values of almost every kind of manufactured goods during two centuries past; a fall accelerated by the mechanical inventions of the last seventy or eighty years, and susceptible of being prolonged and extended beyond any limit which it would be safe to specify. The benefit might even extend to the poorest class. The increased cheapness of clothing and lodging might make up to them for the augmented cost of their food. There is, thus, no possible improvement in the arts of production which does not in one or another mode exercise an antagonistic influence to the law of diminishing return to agricultural labor. Nor is it only industrial improvements which have this effect. Improvements in government, and almost every kind of moral and social advancement, operate in the same manner. We may say the same of improvements in education. The intelligence of the workman is a most important element in the productiveness of labor. The carefulness, economy, and general trustworthiness of laborers are as important as their intelligence. Friendly relations and a community of interest and feeling between laborers and employers are eminently so. In the rich and idle classes, increased mental energy, more solid instruction, and stronger feelings of conscience, public spirit, or philanthropy, would qualify them to originate and promote the most valuable improvements, both in the economical resources of their country and in its institutions and customs. § 5. Law Holds True of Mining. We must observe that what we have said of agriculture is true, with little variation, of the other occupations which it represents; of all the arts which extract materials from the globe. Mining industry, for example, usually yields an increase of produce at a more than proportional increase of expense.