The names of new candidates for election into the Institution were announced and ordered to be suspended. Donations to the Library were announced as having been received since the last meeting from Mr. Wilfred S. Boult, and Sir David Salomons, Bart., to whom the thanks of the meeting were duly accorded. The following paper was then read :-ELECTKIC LIGHTING FEOM CENTEAL STATIONS, WITH SPECIAL EEFEEENCE TO THE CHELSEA SYSTEM. ELECTRIC LIGHTING [Jan. 22nd T reversed, the left half battery will be

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... in charge," and the right half battery discharging ; and, again, that if the inner ends of the two rocking arms are dipped and they stand with opposing angles, then both half batteries are discharging, and charging has ceased. In the perspective diagram below the right is discharging, and the left is charging. Let ns return to what takes place at the moment the arms of the switches rock into a fresh position. Underneath each of these arms, as in the case of those belonging to the charging circuit relays, C 19 C 2 , are placed two electro-magnets to pull them down. These electro-magnets are also placed in the local circuit mentioned twice before. This operation of rocking over, so to speak, is sufficiently slow between the break and make in the mercury-cups as to allow an interval of disconnection of less than half a minute. During this interval the charging current does not cease, but for the time, as has been already described, is relayed through the resistance 0 by the operation of the charging circuit relay C 1} the rocking arm of which, instead of moving slowly like that of the transposing switch, moves instantaneously. The operation is effected in the following order and manner:-As has been stated, the gasholder closes the local circuit in the pull-magnets under the elevated end of the rocking arm of the right-hand transposing switch, which commences to move slowly over, aided by a balance weight rolling in a groove on its upper side. As the charging contacts leave the mercury other contacts under the arm break the current in the pull-down magnet of the outer end of the rocking arm of the. charging relay, which, being weighted, falls the other way, and effects simultaneously the introduction of resistance O. The rocking arm of Aj continues moving slowly over. It first makes the contacts which bring the right half battery into the position of discharge in parallel, and finally makes other contacts, which, acting on the local circuit through a small rocking switch, start the rocking arm of the transposing switch A a . Its first action is to cut the left half battery out of the lamp system, and when it completes its journey to throw the left half battery in series into the charging circuit. At the same moment, by a separate contact, it closes the local circuit which actuates the pull-down magnet of the charging circuit relay C 2 , the effect of which is simultaneously to transfer the charging current from the resistance O to its next duty. "When the left half battery is charged, the next and final stage is carried out by the gasholder acting as before on the local circuit, the work of which is confined to inciting the rocking arm of the left-hand transposing switch to rock over, so that the second half battery goes to the assistance of its fellow. A tell-tale wire back to the generating station from the transposing switch actuates a relay at the generating station the moment that the left-hand contacts lift out of the mercury. The current so transmitted actuates a relay which cuts off steam at the generating station. On each side of the diagram are shown four " resistance" cells of the same type as those for accumulating, marked R, &c. The duty required from them is as follows :-1. To supply counter E.M.F. with which to regulate the pressure in the lamp system. 2. To give the required energy to actuate what has several times been referred to as the local circuit, of which there are actually two-one for each side of the apparatus.