ror "the very age and body of the time, his form and feature," exactly as the romance of our own day shows forth the stir and ferment and turmoil of the present far greater period of national development. A great deal of what most of us take for Shakespeare is really the necessary spirit and background of the Elizabethan stage, as much the common product of the nation at large and of the dramatic tradition as the modern novel or the modern burlesque is the common product of our own civilization.
In science and philosophy, however, this general principle of necessary development is even more demonstrably true than elsewhere. There comes a crisis every now and then in the evolution of thought, when new discoveries and new inventions are, as we all say nowadays, "in the air"; when numberless workers, led up to a certain point by previous thinkers and previous discoveries, tremble all together on the very verge of the next great generalization or the next important extension of thought or knowledge. "He who says A must say B also," the wise French proverb pithily puts it. Now it sometimes happens in such cases that a number of workers co-operate so much in the new discovery, or the new invention, or the new development, that no one man carries off for himself the honors of the situation. That was the case with the vast physical concept of the conservation of energy, by far the vastest and most fundamental concept ever yet introduced into our view of the material cosmos and its mode of working. Yet that profound law was so slowly evolved by the separate labors of many acute and suggestive thinkers, beginning with Count Rumford and ending with Joule, Meyer, Helmholtz, Grove, Clerk Maxwell, Balfour Stewart, and Tait, that no single name will ever probably be associated with its promulgation, as the name of Newton is associated with the law of gravitation, or as the name of Darwin is associated with the principle of organic evolution. More frequently, however, it happens that a particular worker does either anticipate the others by a decided interval, or succeeds at any rate in attracting to himself the attention of the crowd, and in becoming, so to speak, the eponymous hero of the new conquest. In such cases I do not say that the hero is not really as a rule greater than the men he casts into the shade; but I do say that he is not as a rule as much greater as the world at large, in its love for the sweet simplicity of hero-worship, supposes him to be. It is so hard to distribute your praise equitably between a dozen or more of contributory geniuses; it is so easy to fix upon a single man and declare authoritatively in a very loud voice, "Ipse fecit!"
Mechanical inventions show us the working of this popular tendency in a very clear and instructive manner. Who, for example, invented the steam-engine? James Watt, says everybody,