Read it through once

‘The coincidence, however, between Mr. Wallace’s conclusions and those of Mr. Darwin was very remarkable. But, after all, coincidences of this sort have not been uncommon in the history of scientific inquiry. Nor is it at all surprising that they should occur now and then, when we remember that a great and pregnant discovery must always be concerned with some question which many of the foremost minds in the world are busy thinking about. It was so with the discovery of the differential calculus, and again with the discovery of the planet Neptune. It was so with the interpretation of the Egyptian hieroglyphics, and with the establishment of the undulatory theory of light. It was so, to a considerable extent, with the introduction of the new chemistry, with the discovery of the mechanical equivalent of heat, and the whole doctrine of the correlation of forces. It was so with the invention of the electric telegraph and with the discovery of spectrum analysis. And it is not at all strange that it should have been so with the doctrine of the origin of species through natural selection.’