The greater part of the men who constitute these nations are extremely eager in the pursuit of actual and physical gratification. As they are always dissatisfied with the position which they occupy, and are always free to leave it, they think of nothing but the means of changing their fortune, or of increasing it. To minds thus predisposed, every new method which leads by a shorter road to wealth, every machine which spares labor, every instrument which diminishes the cost of production, every discovery which facilitates pleasures or augments them, seems to be the grandest effort of the human intellect. It is chiefly from these motives that a democratic people addicts itself to scientific pursuits--that it understands, and that it respects them. In aristocratic ages, science is more particularly called upon to furnish gratification to the mind; in democracies, to the body. You may be sure that the more a nation is democratic, enlightened, and free, the greater will be the number of these interested promoters of scientific genius, and the more will discoveries immediately applicable to productive industry confer gain, fame, and even power on their authors. For in democracies the working class takes a part in public affairs; and public honors, as well as pecuniary remuneration, may be awarded to those who deserve them. In a community thus organized it may easily be conceived that the human mind may be led insensibly to the neglect of theory; and that it is urged, on the contrary, with unparalleled vehemence to the applications of science, or at least to that portion of theoretical science which is necessary to those who make such applications. In vain will some innate propensity raise the mind towards the loftier spheres of the intellect; interest draws it down to the middle zone. There it may develop all its energy and restless activity, there it may engender all its wonders. These very Americans, who have not discovered one of the general laws of mechanics, have introduced into navigation an engine which changes the aspect of the world.