Next to those who worked with Edison at the laboratory and were with him constantly at Menlo Park were the visitors, some of whom were his business associates, some of them scientific men, and some of them hero-worshippers and curiosity-hunters. Foremost in the first category was Mr. E. H. Johnson, who was in reality Edison's most intimate friend, and was required for constant consultation; but whose intense activity, remarkable grasp of electrical principles, and unusual powers of exposition, led to his frequent detachment for long trips, including those which resulted in the introduction of the telephone, phonograph, and electric light in England and on the Continent. A less frequent visitor was Mr. S. Bergmann, who had all he needed to occupy his time in experimenting and manufacturing, and whose contemporaneous Wooster Street letter-heads advertised Edison's inventions as being made there, Among the scientists were Prof. George F. Barker, of Philadelphia, a big, good-natured philosopher, whose valuable advice Edison esteemed highly. In sharp contrast to him was the earnest, serious Rowland, of Johns Hopkins University, afterward the leading American physicist of his day. Profs. C. F. Brackett and C. F. Young, of Princeton University, were often received, always interested in what Edison was doing, and proud that one of their own students, Mr. Upton, was taking such a prominent part in the development of the work. Soon after the success of the lighting experiments and the installation at Menlo Park became known, Edison was besieged by persons from all parts of the world anxious to secure rights and concessions for their respective countries. Among these was Mr. Louis Rau, of Paris, who organized the French Edison Company, the pioneer Edison lighting corporation in Europe, and who, with the aid of Mr. Batchelor, established lamp-works and a machine-shop at Ivry sur-Seine, near Paris, in 1882. It was there that Mr. Nikola Tesla made his entree into the field of light and power, and began his own career as an inventor; and there also Mr. Etienne Fodor, general manager of the Hungarian General Electric Company at Budapest, received his early training. It was he who erected at Athens the first European Edison station on the now universal three-wire system. Another visitor from Europe, a little later, was Mr. Emil Rathenau, the present director of the great Allgemeine Elektricitaets Gesellschaft of Germany. He secured the rights for the empire, and organized the Berlin Edison system, now one of the largest in the world. Through his extraordinary energy and enterprise the business made enormous strides, and Mr. Rathenau has become one of the most conspicuous industrial figures in his native country. From Italy came Professor Colombo, later a cabinet minister, with his friend Signor Buzzi, of Milan. The rights were secured for the peninsula; Colombo and his friends organized the Italian Edison Company, and erected at Milan