But not alone are these material results worthy of notice. Others of a moral and social kind force themselves on our attention. Four million negro slaves had been set free. Legislation, if it inclined to the advantage of any class, inclined to that of the poor. Its intention was to raise them from poverty, and better their lot. A career was open to talent, and that without any restraint. Every thing was possible to intelligence and industry. Many of the most important public offices were filled by men who had risen from the humblest walks of life. If there was not social equality, as there never can be in rich and prosperous communities, there was civil equality, rigorously maintained. It may perhaps be said that much of this material prosperity arose from special conditions, such as had never occurred in the case of any people before, There was a vast, an open theatre of action, a whole continent ready for any who chose to take possession of it. Nothing more than courage and industry was needed to overcome Nature, and to seize the abounding advantages she offered. ILLUSTRATIONS FROM AMERICAN HISTORY. But must not men be animated by a great principle who successfully transform the primeval solitudes into an abode of civilization, who are not dismayed by gloomy forests, or rivers, mountains, or frightful deserts, who push their conquering way in the course of a century across a continent, and hold it in subjection? Let us contrast with this the results of the invasion of Mexico and Peru by the Spaniards, who in those countries overthrew a wonderful civilization, in many respects superior to their own--a civilization that had been accomplished without iron and gunpowder--a civilization resting on an agriculture that had neither horse, nor ox, nor plough. The Spaniards had a clear base to start from, and no obstruction whatever in their advance. They ruined all that the aboriginal children of America had accomplished. Millions of those unfortunates were destroyed by their cruelty. Nations that for many centuries had been living in contentment and prosperity, under institutions shown by their history to be suitable to them, were plunged into anarchy; the people fell into a baneful superstition, and a greater part of their landed and other property found its way into the possession of the Roman Church. I have selected the foregoing illustration, drawn from American history, in preference to many others that might have been taken from European, because it furnishes an instance of the operation of the acting principle least interfered with by extraneous conditions. European political progress is less simple than American. QUARREL BETWEEN FRANCE AND THE PAPACY. Before considering its manner of action, and its results, I will briefly relate how the scientific principle found an introduction into Europe.