individual, who in most cases is not consciously aware of the fact, with such an abundance of preliminary knowledge that with this equipment he can more easily take further steps on the road of progress. The boy of to-day, for example, grows up among such an overwhelming mass of technical achievement which has accumulated during the last century that he takes as granted many things which a hundred years ago were still mysteries even to the greatest minds of those times. Yet these things that are not so much a matter of course are of enormous importance to those who would understand the progress we have made in these matters and would carry on that progress a step farther. If a man of genius belonging to the 'twenties of the last century were to arise from his grave to-day he would find it more difficult to understand our present