Notes: Tesla Apparatus

Friday, February 5, 1892
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THE ELECTRICAL ENGINEERING, INDUSTRY AND SCIENCE. No. 716.-vor.. XXVIII. FRIDAY, FEBRUARY 5, 1892. "MCE s‘¥"E“°E~ NOTES. __,__. To say that a large audience was enchanted by the long- expected lecture of Mr. Nxxom Tasmi on Wednesday night is no exaggeration; for as soon as he grasped his long glass tubes they glowed with softened splendour, as, magiciandike, he waved them over his head, and little bulbs of glass \vith phosphoreseing powder gleamed with a weird, if not ghastly, radiance when merely hung on his finger tip. Vainly did the unscientihc members of the audience whisper to their neigh~ bours, “ How is it done ? ” And in his enthusiasm the lecturer, who seemed to love his wonderful lamps and globes, forgot to give an explanation. The more initiated' flinehed at the ominous crackle .of the high-pressure discharges, and looked with some apprehension at a wooden box in which a magnetic interrupter was enclosed, and from which flames rose when the current was turned on. But the flames were shut down with an ordinary wooden lid, and the spluttering terminals shot out angry discharges at an iron clamp which the lecturer presented to it when he wished to convoy a few huudrod thousand volts through his body to a vacuum tube. _Qi T1-is apparatus used by l\Ir. Nikona Tssm is of thc simplest description, but the arrangement of the subsidiary parts is complicated, and the adjustments are numerous and diilicult to make. ,The high-frequency dynamo, which was placed in the dynamo-room of the Royal Institution, is most remarkable for its unsophistieatcd and plain design. It consists of a. stationary armature, about 30 inches diameter, with 880 inwardly projecting coils, like those of a Parker alternator. A thin iron disc, like a fine-pitch gear wheel, is provided with 880 tiny magnets connected-up in series, runs with very small clearance, and generates a current with some 18,000 periods per second. This dynamo and several of the more characteristic experiments were described and illustrated in The ]u'lr1-triciaiz, Vol. XXVII., p. 382. But no illustrations can convey an idea of the beautiful effects to those who have not seen them; and no report of the lecture can give to those who were not present, such an insight into Mr. Nniom 'l‘ssr.A’s attractive personality as it was the privilege of his audience to enjoy. _._ . Tas audience which gathers at the meetings of the Institu~ tion of Electrical Engineers is, probably, the most youthful of any scientific society; but several of the well-known men Annual samnpam (1/.K.), 19/s who often attend and take part in the proceedings are not members ofthe Institution. The Institution of Civil Engi< ncers not only oiiers admirable accommodation, but providesa few members who contribute very usefully to the discussions. Some of these have been startled to find that their prero- gative as members of the older Institution was of no avail for gaining admission to Mr. Nmom T|:1SLA’S lecture, and had to beg for tickets from members of the Institution of Electrical Engineers. That these tickets could be used for admitting strangers to the theatre of the Royal Institution came as a surprise when announcement was made to this effect after Prof. AYn'roN's address; but this hope \vas rudely shattered by a circular, dated February 1st, which withdrew this privil lege. As a last resource, several country members \vere appealed to by telegraph, and were good enough to send their post cards to their more fortunate London friends. By a fortunate combination of *circumstances the theatre was just full, and no one was turned away. We understand that the Institution of Civil Engineers can accommodate only 400, and that the audience on Wednesday numbered about 800.