beam upon the interior of a tube. We have thus heard from interrupted sunlight very perceptible musical tones through tubes of ordinary vulcanized rubber, of brass, and of wood. These were all the materials at hand in tubular form, and we have had no opportunity since of extending the observations to other substances. A musical tone can be heard by throwing the intermittent beam of light into the ear itself. This experiment was at first unsuccessful on account of the position in which the ear was held.” CHAPTER XXVII BESSEMER, CREATOR OF CHEAP STEEL. NOBEL, INVENTOR OF NEW EXPLOSIVES Bessemer a man of golden ignorances . . . His boldness and versatility . . . The story of his steel process told by himself . . . Nobel’s heroic courage in failure and adversity . . . His triumph at last . . . Turns an accidental hint to great profit . . . Inventors to-day organized for attacks of new breadth and audacity. Bessemer’s Early Achievements. In 1855 Henry Bessemer began to change the face of the civilized world as he perfected his process for steel-making. The story of his struggles, defeats and eventual triumph is told in his autobiography published in London by _Engineering_.[35] From that book the publishers have permitted the following pages to be drawn. As a boy Henry Bessemer had a strong mechanical turn, amusing himself with a lathe at an age when lads usually prefer marbles or tag. In his youth there was a clear promise of inventive faculty, plainly inherited from his father, Anthony Bessemer, and naturally pursuing the lines of paternal interests. Mr. Bessemer, senior, manufactured type of particular durability; this quality his son discovered due to additions of a little tin and copper to the ordinary alloy. It was in this field of alloying that young Bessemer took his next step as an inventor, foreshadowing the tremendous feat he was in due time to accomplish. He busied himself as an engraver of rollers for embossing paper; in cutting their deeply incised lines there was a tendency in curves to drag or blur the surface of the metal. After several unsuccessful attempts he produced an alloy of tin and bismuth free from this fault. [35] “Sir Henry Bessemer: an Autobiography.” Offices of _Engineering_, 36 Bedford St., Strand, London, 1905. 16 shillings.