Since the erection of plant by these works at Solothurn for transmitting 50 horse power five miles distant, which attracted so much interest some time ago, several important works have been carried out. Among these we may mention a 280 horse power transmission at 1½ kilom. distance to a cotton mill at Derendingen in Switzerland, a 250 horse power transmission at ½ kilom. distance, carried out for Gaetano Rossi at Piovene in Italy, and a 300 horse transmission at 6 kilom. distance installed for Giovanni Rossi, in which the power is given off at two different stations.--_The Engineer._
Although telephonic novelties are not numerous at the Universal Exposition, telephony--that quite young branch of electric science--is daily the object of curious and interesting experiments which we must make known to our readers, a large number of whom were not yet born to scientific life when the experiments were made for the first time at Paris in 1881; and it is proper to congratulate the Société Générale des Téléphones on having repeated them in 1889 to the great satisfaction of the rising generation.
We allude to the Ader system of telephonic transmissions of sounds in such a way that they can be heard by an audience.
The essential parts of this mode of transmission consist of two distinct systems--transmitters and receivers.
[Illustration: FIG. 1.--THE ADER FLOURISH OF TRUMPETS]
The transmitters are four in number, and are actuated by the same number of musicians, each humming into them his part of the quartet (Fig. 1). This transmitter, represented apart in elevation and section in Fig. 2, is identical with the one used in the curious experiment with the singing condenser. At A is a mouthpiece before which the musician hums his part as upon a reed pipe. He causes the plate, B, to vibrate in unison with the sound that he emits, and this produces periodical interruptions of varying rapidity between the disk, B, and the point, C. The button, D, serves to regulate the distance in such a way that the breakings of the circuit shall be very complete and produce sounds in the receivers as pure as allowed by this special mode of transmission, in which all the harmonics are systematically suppressed in order to re-enforce the fundamental.
