First of all, there are great men who discover general truths, great ideas, universal laws, or invent methods of thought and action. In this class the vastness of a man's genius may be measured, and his relative rank ascertained by the transcendency of his ideas, by the newness of his truth, by its practical value, and the difficulty of attaining it in his time, and under his peculiar circumstances. In literature it is such men who originate thoughts, and put them into original forms; they are the great men of letters. In philosophy we meet with such; and they are the great men of science. Thus Socrates discovered the philosophical method of minute analysis that distinguished his school, and led to the rapid advance of knowledge in the various and even conflicting academies, which held this method in common, but applied it in various ways, well or ill, and to various departments of human inquiry; thus Newton discovered the law of gravitation, universal in nature, and by the discovery did immense service to mankind. In politics we find similar, or analogous men, who discover yet other laws of God, which bear the same relation to men in society that gravitation bears to the orbs in heaven, or to the dust and stones in the street; men that discover the first truths of politics, and teach the true method of human society. Such are the great men in politics. We find corresponding men in religion; men who discover an idea so central that all sectarianism of parties or of nations seems little in its light; who discover and teach the universal law which unifies the race, binding man to man, and men to God; who discover the true method of religion conducting to natural worship without limitation, to free piety, free goodness, free thought. To my mind such are the greatest of great men, when measured by the transcendency of their doctrine and the service they render to all. By the influence of their idea, letters, philosophy, and politics become nobler and more beautiful, both in their forms and their substance. Such is the class of discoverers; men who get truth at first hand, truth pertaining either especially to literature, philosophy, politics, religion, or at the same time to each and all of them. * * * * * The next class consists of such as organize these ideas, methods, truths, and laws; they concretize the abstract, particularize the general; they apply philosophy to practical purposes, organizing the discoveries of science into a railroad, a mill, a steam-ship, and by their work an idea becomes fact. They organize love into families, justice into a state, piety into a church. Wealth is power, knowledge is power, religion power; they organize all these powers, wealth, knowledge, religion, into common life, making divinity humanity, and that society.