Schrotter had not let the suggestion drop which he made at Dorfling's dinner-party, and had persuaded Wilhelm so long that he finally rouse himself to attempt an account of the ways and means by which the human mind has freed itself of its grossest errors.

It was to be entitled "A History of Human Ignorance," and promised to be a most original work.

He would endeavor to show what idea people had had of the universe at various periods, how they explained the phenomena of nature, their connection, their causes and effects.

He would begin with the childish superstitions of the savages, and continuing through the so-called learned systems of the ancients and of the Middle Ages, would bring his history up to the theories of contemporary scientists.

He would demonstrate the psychological causes of the fact that man, at a certain stage of intellectual development, must necessarily fall into certain errors, and by the aid of what experiments, experiences, and conclusions he had come gradually to recognize them as such.