The inventors who made possible the prodigious mechanical progress of the past century are, for the most part, forgotten; only a few names, such as those of Watt, Stephenson, Fulton, Whitney, and Morse being known, and those dimly, to the public. Some, like Palissy the potter, are remembered for the fascination of their biography, their heroic persistence, strokes of good fortune or the like; and probably it is safe to conclude that few men of this class would be famous for their inventions alone. As Doctor Johnson remarks in The Rambler,[26] the very fact that an idea is wholly successful may cause its originator to be forgotten. “It often happens that the general reception of a doctrine obscures the books in which it was delivered. When any tenet is generally received and adopted as an incontrovertible principle, we seldom look back to the arguments upon which it was first established, or can bear that tediousness of deduction and multiplicity of evidence by which its author was forced to reconcile it to prejudice and fortify it in the weakness of novelty against obstinacy and envy.” He instances “Boyle’s discovery of the qualities of the air”; and I suppose that if Darwin’s views could have been easily accepted, instead of meeting the bitter and enduring opposition of theological and other traditions, his popular fame would have been comparatively small. He is known to the many chiefly as the symbol of a militant cause. It is, then, present function, not past, which is the cause of fame, and any change which diminishes or enhances this has a parallel effect upon reputation. Thus the fame of Roger Bacon was renewed after an obscurity of six centuries, because it came to be seen that he was a significant forerunner of contemporary scientific thought; and Mendel, whose discovery of a formula of heredity was at first ignored, became famous when biology advanced to a point where it could appreciate his value. There are many cases in the annals of art of men, like Tintoretto or Rembrandt, whose greatest fame was not attained until the coming of a later generation more in harmony with them than were their contemporaries.