“Die in Fig. 11 angewendeten Rollen sind in Fig. 12 detailliert gezeichnet. Auf einer kreisförmigen Scheibe C aus weichem Eisen erhebt sich in der Mitte derselben ein hohler Cylinder b aus Holz oder anderem isolirten Materiale; um den unteren Teil des letzteren ist die Hauptspirale a gewickelt, welche aus bandförmigen Kupferstreifen oder anderem Metalle besteht, a′ ist die in gleicher Weise zusammengesetzte Induktionsspirale, deren Drahtenden zu den Lichtherden führen. Zwischen den einzelnen Windungen der Spirale sind Streifen aus Papierkarton oder einem anderen isolirenden Material angebracht. Die Spirale a ist in die Hauptleitung, wie Fig. 11 zeigt, eingeschaltet.”
The second claim of this patent is also interesting, and reads as follows:—
“Die Einführung einer Serie von Induktionsrollen in den Umkreis eines beliebigen Elektricitätsgenerators zur Erzeugung einer Serie von Induktionsströmen, welche es gestatten, Lichtherde von verschiedener Intensität durch eine einzige Elektricitätsquelle zu versorgen, was zur vollständigen Teilbarkeit des elektrischen Lichtes führt.”
Jablochkoff’s system as just described was to be seen working in the Paris Exhibition of the year 1878. A proper industrial application of this system does not appear to have taken place.
C. T. & E. B. Bright, 1878.
In the year 1878 the brothers Bright had also made further progress in the use of induction coils for electric lighting purposes, and in the same year they took out the English patent No. 4212, in which they described the use of alternating currents for working secondary apparatus or induction coils placed at various points where light was required. We shall here quote some very interesting sentences from this patent, which again show that the brothers Bright knew already in the year 1878 the properties of transformers suiting them for electric lighting purposes; indeed they then anticipated the principles contained in the later patent of Gaulard. Here is an abstract from the description:—
“At each point where electric light is used, the electric lamps or groups of such lamps are fed by the secondary coil or coils of an induction apparatus placed there. The primary coils of all the induction apparatus are in the common circuit of one main lead, which is in connection with a battery or a magneto-electric machine placed in some suitable situation. The size and length of the primary and secondary coils of each induction apparatus is determined according to the number of lamps at each point, where the secondary current shall supply the electric lighting.”
E. Edwards & A. Normandy, 1878.
The employment of induction coils for the distribution of light, heat, and power was patented in England in the same year by Edmund Edwards and Alphonse Normandy. Among other matter in this patent there is as follows:—
“At or near every point where it is required that a light shall be produced, we arrange a coil (or series of coils) of insulated metallic wire or ribbon (preferably surrounding a bar or wires of soft iron), through which coil or coils the current from the principal wire first described can be passed when desired, or cut off by means of a key or lever. Round, or adjacent to, each coil of insulated wire described, we form one or more secondary coils of insulated metallic wire, or ribbon, arranged so that the passage of the rapidly intermittent current of electricity, as described, through the primary coil or coils, generates a corresponding current of electricity in each of the secondary coils.”