Another of the men who might be appropriately included in any comprehensive list of aiders and abettors of the present telegraph system were Leonard D. Gale, then Professor of Chemistry in the University of New York, and Professor Joseph Henry, who had made, and was apparently indifferent to the importance of it because there was no alphabet to use it with, the first electric telegraph ever constructed to be read, or used, _by sound_. Last, though hardly least if all facts are understood, might be included a skillful youth named William Baxter, afterwards known as the inventor of the "Baxter Engine," who, shut in a room with Vail in a machine shop in New Jersey, made in conjunction with the author of the alphabet the first telegraphic instrument that, with Henry's magnet and battery cells, sent across space the first message ever read by a person who did not know what the words of the message would say or mean until they had been received. After the telegraph the state of electrical knowledge was for a long time such that electrical invention was in a sense impossible. The renowned exploit of Field was not an invention, but a heroic and successful extension of the scope and usefulness of an invention. But thought was not idle, and filled the interval with preparations for final achievements unequaled in the history of science. Two of these results are the electric light and the telephone. For the various "candles," such as that of Jablochkoff, exhibited at Paris in 1870, only served to stimulate investigation of the alluring possibilities of the subject. The details of these great inventions are better known than those of any others. The telegraph and the newspaper reporter had come upon the field as established institutions. Every process and progress was a piece of news of intense interest. When the light glowed in its bulb and sparkled and flashed at the junction points of its chocolate-colored sticks it had been confidently expected. There was little surprise. The practical light of the world was considered probable, profitable, and absolutely sure. The real story will never be told. The thoughts, which phrase may also include the inevitable disappointments of the inventor, are never written down by him. That variety of brain which, with a few great exceptions, was not known until modern, very recent times, which does not speculate, contrive, imagine only, but also reduces all ideas to _commercial_ form, has yet to have its analysis and its historian, for it is to all intents a new phase of the evolution of mind. [Illustration: THOMAS A. EDISON.]