as a transmitter, and has been abandoned except for receiving; the Blake, Ader, or some other modification of the microphone being used in conjunction with a separate battery.  To avoid complication in the drawings, however, the simplest case is taken.  And it must be understood that instead of the single instrument shown at T1 or T2, a complete set of telephonic instruments, including transmitter, battery, induction-coil, and receiver or receivers, may be substituted.  And if a shunt, S, of 500 ohms placed across the circuit makes no difference to the talking in the telephones because of the interposition of the separating condenser, C, it will readily be understood that a telegraphic system properly “graduated,” and having also a resistance of 500 ohms, will not affect the telephones if interposed in the place of S. This arrangement is shown in Fig. 3, where the “graduated” telegraph-set from Fig. 1 is intercalated into the telephonic system of Fig. 2, so that both work simultaneously, but independently, through a single line.  The combined system at each end of the line will then consist of the telephone-set, T1, the telegraph instruments (comprising battery, B1, key, M1 and Morse receiver, R1), the “graduating” electromagnets, E1, and E2, the “graduating” condenser, C1, and the “separating” condenser, C2.  It was found by actual experiments that the same arrangement was good for lines varying from 28 to 200 miles in length.  A single wire between Brussels, Ghent, and Ostend is now regularly employed for transmission by telegraph of the ordinary messages and of the telemeteorographic signals between the two observatories at those places, and by telephone of verbal simultaneous correspondence, for one of the Ghent newspapers.  A still more interesting arrangement is possible, and is indicated in Fig. 4.  Here a separating condenser is introduced at the intermediate station at Ghent between earth and the line, which is thereby cut into two independent sections for telephonic purposes, while remaining for telegraphic purposes a single undivided line between Brussels and Ostend.  Brussels can telegraph to Ostend, or Ostend to Brussels, and at the same time the wire can be used to telephone between Ghent and Ostend, or between Ghent and Brussels, or both sections may be simultaneously used.

[Illustration:  Fig. 3]

[Illustration:  Fig. 4]

It would appear, then, that M. Van Rysselberghe has made an advance of very extraordinary merit in devising these combinations.  We have seen in recent years how duplex telegraphy superseded single working, only to be in turn superseded by the quadruplex system.  Multiplex telegraphy of various kinds has been actively pursued, but chiefly on the other side of the Atlantic rather than in this country, where our fast-speed automatic system has proved quite adequate hitherto.  Whether we shall see the adoption in the United Kingdom of Van Rysselberghe’s system is, however, by no means certain.  The essence of it consists in retarding the telegraphic signals to a degree quite incompatible with the fast-speed automatic transmission of telegraphic messages in which our Post Office system excels.  We are not likely to spoil our telegraphic system for the sake of simultaneous telephony, unless there is something to be gained of much greater advantage than as yet appears.—­Nature.