“With reference to originality in all departments, whether science, practice, or fine art, there is a point of character that deserves notice, as being more obviously of value in practical inventions and in the conduct of business and affairs--I mean an active turn, or a profuseness of energy, put forth in trials of all kinds on the chance of making lucky hits. In science, meditation and speculation can do much, but in practice, a disposition to try experiments is of the utmost service. Nothing less than a fanaticism of experimentation could have given birth to some of our grandest practical combinations. The great discovery of Daguerre, for example, could not have been regularly worked out by any systematic and orderly research; there was no way but to stumble upon it, so unlikely and remote were the actions brought together in one consecutive process. The discovery is unaccountable, until we learn that the author had been devoting himself to experiments for improving the diorama, and thereby got deeply involved in trials and operations far removed from the beaten paths of inquiry. The energy that prompts to endless attempts was found in a surprising degree in Kepler. A similar untiring energy--the union of an active temperament with intense fascination for his subject--appears in the character of Sir William Herschel. When these two attributes are conjoined; when profuse active vigor operates on a field that has an unceasing charm for the mind, we then see human nature surpassing itself. “The invention of photography by Daguerre illustrates the probable method whereby some of the most ancient inventions were arrived at. The inventions of the scarlet dye, of glass, of soap, of gunpowder, could have come only by accident; but the accident, in most of them, would probably fall into the hands of men engaged in numerous trials upon the materials involved. Intense application--‘days of watching, nights of waking’--went with ancient discoveries, as well as with modern. In the historical instances, we know as much. The mental absorption of Archimedes is a proverb. “The wonderful part of Daguerre’s discovery consists in the succession of processes that had to concur in one operation before any effect could arise. Having taken a silver plate, iodine is first used to coat the surface; the surface is then exposed to the light, but the effect produced is not apparent till the plate has been immersed in the vapor of mercury. To fall upon such a combination, without any clue derived from previous knowledge, an innumerable series of fruitless trials must have been gone through.