This volume represents an effort in the direction of what may be called the biographical history of electricity. The controlling idea in its preparation was to provide brief yet reasonably complete sketches of the lives of the great pioneer workers in electricity, the ground-breaking investigators who went distinctly beyond the bounds of what was known before their time, not merely to add a fringe of information to previous knowledge, but to make it easy for succeeding generations to reach conclusions in electrical science that would have been quite impossible until their revealing work was done. The lives of these men are not only interesting as scientific history, but especially as human documents, showing the sort of men who are likely to make great advances in science and, above all, demonstrating what the outlook of such original thinkers was on all the great problems of the world around us.

In recent times, many people have come to accept the impression that modern science leads to such an exclusive occupation with things material, that scientists almost inevitably lose sight of the deeper significance of the world of mystery in which humanity finds itself placed on this planet. The lives of these great pioneers in electricity, however, do not lend the slightest evidence in confirmation of any such impression. They were all of them firm believers in the existence of Providence, of a Creator, of man's responsibility for his acts to that Creator, and of a hereafter of reward and punishment where the sanction of responsibility shall be fulfilled. Besides, they were men characterized by some of the best qualities in human nature. Their fellows liked them for their unselfishness, for their readiness to help others, for their devotedness to their work and to their duties as teachers, citizens and patriots. Almost without exception, they were as far above the average of mankind in their personal ethics as they were in their intellectual qualities.

The lives of such men, who were inspiring forces in their day, are as illuminating as they are instructive and encouraging. Perhaps never more than now do we need such inspiration and illumination to lift life to a higher plane of purpose and accomplishment, than that to which it is so prone to sink when material interests attract almost exclusive attention.