As an example, let us take a very short period of French history, merely that from 1790 to 1820, a period of thirty years' duration, that of a generation. In the course of it we see the crowd at first monarchical become very revolutionary, then very imperialist, and again very monarchical. In the matter of religion it gravitates in the same lapse of time from Catholicism to atheism, then towards deism, and then returns to the most pronounced forms of Catholicism. These changes take place not only amongst the masses, but also amongst those who direct them. We observe with astonishment the prominent men of the Convention, the sworn enemies of kings, men who would have neither gods nor masters, become the humble servants of Napoleon, and afterwards, under Louis XVIII., piously carry candles in religious processions. Numerous, too, are the changes in the opinions of the crowd in the course of the following seventy years. The "Perfidious Albion" of the opening of the century is the ally of France under Napoleon's heir; Russia, twice invaded by France, which looked on with satisfaction at French reverses, becomes its friend. In literature, art, and philosophy the successive evolutions of opinion are more rapid still. Romanticism, naturalism, mysticism, &c., spring up and die out in turn. The artist and the writer applauded yesterday are treated on the morrow with profound contempt. When, however, we analyse all these changes in appearance so far reaching, what do we find? All those that are in opposition with the general beliefs and sentiments of the race are of transient duration, and the diverted stream soon resumes its course. The opinions which are not linked to any general belief or sentiment of the race, and which in consequence cannot possess stability, are at the mercy of every chance, or, if the expression be preferred, of every change in the surrounding circumstances. Formed by suggestion and contagion, they are always momentary; they crop up and disappear as rapidly on occasion as the sandhills formed by the wind on the sea-coast. At the present day the changeable opinions of crowds are greater in number than they ever were, and for three different reasons. The first is that as the old beliefs are losing their influence to a greater and greater extent, they are ceasing to shape the ephemeral opinions of the moment as they did in the past. The weakening of general beliefs clears the ground for a crop of haphazard opinions without a past or a future. The second reason is that the power of crowds being on the increase, and this power being less and less counterbalanced, the extreme mobility of ideas, which we have seen to be a peculiarity of crowds, can manifest itself without let or hindrance.