depending at every step upon scientific attainment and application. With the increasing crowd of workers, and the vast and ever-expanding field of work, no one could hope to be of any great service to the world, or leave his mark behind him, who aimed to try his hand or his head at many different things. Those who stuck to some one subject, which, with its limitation of range, they were able thoroughly to master, were most likely to rise to the position of authorities upon such a limited range, and to be listened to by the rest of the world.
Thus science, when pursued by each of its countless students, within their respective small enclosures, but with thorough and continuous study, made collectively a giant progress. As most people began, about this time, to be content to work in this quiet but effective way, they became masters and authorities in their respective specialities; and thus the vast army of workers, each soldier within his own particular range, advanced the boundaries of science by ever increasing observation and discovery.
At the close of the nineteenth century, society had indeed already entered, but only to the mere threshold, of a vast field of progress. There was some slight foretaste of that progress during the last half of that century, when, besides the ordinary electric telegraph, introduced just a little while before, the spectroscope, the telephone, the microphone, the photophone, and such-like, came successively crowding upon the raw and astonished world of that primitive day, and when electric light was everywhere empowering us to turn night into brilliant day. In due time succeeded the far grander discovery of the
