existence, and who believe that it really moves as the observer moves—occasionally, indeed, as I can testify, expressing surprise at the fact. But, apart from the observer, there exists no such bar of light; nor when the observer moves is there any movement of this glittering line of wavelets. All over the dark part of the surface the undulations are just as bright with moonlight as those he sees; but the light reflected from them does not reach his eyes. Thus, though there seems to be a lighting of some wavelets and not of the rest, and though, as the observer moves, other wavelets seem to become lighted that were not lighted before, yet both these are utterly false seemings. The simple fact is, that his position in relation to certain wavelets brings into view their reflections of the moon's light, while it keeps out of view the like reflections from all other wavelets.
Sociological evidence is largely vitiated by illusions thus caused. Habitually the relations of observers to the facts are such as make visible the special, and exceptional, and sensational, and leave invisible the commonplace and uninteresting, which form the great body of the facts. And this, which is a general cause of deceptive appearances, is variously aided by those more special causes above indicated; which conspire to make the media, through which the facts are seen, transparent in respect of some and opaque in respect of others.
IN tracing the history of the civilization and growth of humanity, it becomes noticeable that long periods of time often witness but slow and gradual progress; but that from time to time a few inventions and discoveries of eminent men suddenly kindle a revolution in all the spheres of human affairs. To trace to their source the changes so wrought, presents to the historian and scientist one of the most interesting subjects. In nearly every place, the most ancient of such great events, the invention of language and of written characters, are wrapped in complete darkness. As history can be handed down to posterity by means of language only, it is obvious that ages without language can have no history. It is language which introduces nations into history. As regards written speech the case is somewhat different. The most distinguished people of antiquity, the Greeks, emerged from obscurity into history with a language wonderfully complete, but without written characters. During several centuries the Homeric songs had to wan-
- Translated from the German, by C. L. Hotze, Teacher of Physics and Chemistry in the High School of Cleveland, Ohio.