Anyone who enters on the perilous paths of Bibliography realizes, sooner or later, the truth that “of the making of books there is no end.” But there was a beginning: and if the Bibliography of Electricity promises to stretch onward into the future in endless line, at least its backward reach might seem to be finite in date. Nevertheless, the student of the early periods of book production, when the science of electricity was literally in that “infancy” from which in our time it has emerged, is continually finding that there are early works of which he was unaware, and of which even our best libraries are destitute. He finds, as he progresses backward, toward the origins of things, in how many points our ancestors in the domain of electric science had anticipated the discoveries of later date. He finds that, again and again, by some rare stroke of insight, the great minds that had devoted themselves to the research of phenomena had seen--it may be, with dim or imperfect glimpses--many of the things which are commonly regarded as quite modern. The pioneer, unbiased by the views of contemporary philosophers, unhampered by the load of textbook tradition, often sees further than the professed researcher who comes after him. The art of scientific discovery--for it is an art--can be attained in but one way, the way of attainment in all arts, namely, by practising it. In the practice of art, the aspirant may at least learn something that all the textbooks cannot drill out of him, and which will help him in his practice, by the careful examination of the actual ways in which the discoveries of science, now facts of history, were actually made. But, to do this, he must throw overboard for a time the systematic textbooks, he must abandon the logical expositions which embody, at second hand, or at third hand, the antecedent discoveries, and he must go to the original sources, the writings and records of the discoverers themselves, and learn from them how they set to work. The modern compendious handbooks in which the results of hundreds of workers have been boiled down, as it were, to a uniform consistency, is exactly the intellectual pabulum which he must eschew. Let him read Faraday, not through the eyes of Maxwell or of Tyndall, but in his own words in the immortal pages of the “Experimental Researches,” with their wealth of petty detail and their apparent vagueness of speculation. Let him read Ohm’s own account of the law of the circuit, not some modern watered-down version. Let him turn over the pages of Franklin’s letters to Collinson, as his observations dropped red-hot out of the crucible of his endeavours. Let him read Stephen Gray’s charming experiments in the old-world diction that befitted a pensioner of the Charterhouse. Let him go back to old Gilbert, who had talked with Drake and Sir Walter Raleigh in the flesh, who had discussed magnetism with Fra Paolo Sarpi and had experimented on the dip of the needle with Robert Norman.