Page:Proceedings of the Royal Society of London Vol 4.djvu/276

Rh lasting for a second, the instrument now described, although unpro- vided with any internal maintaining or regulating power, would per- form all the usual functions of a perfect clock. The manner in which this apparatus is applied to the clocks, so that the movements of the hands of both may be perfectly simultaneous, is the following. On the axis which carries the scape-wheel of the primary clock a small disc of brass is fixed, which is first divided on its circumference into sixty equal parts ; each alternate division is then cut out and filled with a piece of wood, so that the circumference consists of thirty regular aiteriiations of wood and metal. An extremely light brass spring, which is screwed to a block of ivory or hard wood, and which has no connexion with the metallic parts of the clock, rests by its free end on the circumference of the disc. A copper wire is fastened to the fixed end of the spring, and proceeds to one end of the wire of the electro-magnet; while another wire attached to the clock-frame is continued until it joins the other end of that of the same electro- magnet. A constant voltaic battery, consisting of a few elements of very small dimensions, is interposed in any part of the circuit. By this arrangement the circuit is periodically made and broken, in consequence of the spring resting for one second on a metal division, and the next second on a wooden division. The circuit may be ex- tended to any length ; and any number of electro-magnetic instru- ments may be thus brought into sympathetic action with the standard clock. It is only necessary to observe, that the force of the battery and the proportion between the resistances of the electro-magnetic coils and those of the other parts of the circuit, must, in order to produce the maximum effect with the least expenditure of power, be varied to suit each particular case.

In the concluding part of the paper the author points out several other and very different methods of efirecting the same purpose ; and in particular one in which Faraday's magneto- electric currents are employed, instead of the current produced by a voltaic battery ; he also describes a modification of the sympathetic instrument, calcu- lated to enable it to act at great distances with a weaker electric cur- rent than if it were constructed on the plan first described.

Lieut.-Colonel William Henry Sykes, on the part of the Auditors of the Treasurer's Accounts, reported that the total receipts during the last year, inclusive of a balance of 1808/. 95. Id., carried from the account of the preceding year, amounted to 51251. Ss. \0d. : that the total payments in the same period amounted to 4787/. 9-5. Sd^ leaving a balance in the hands of the Treasurer of 937/- 19*. Id.

The Thanks of the Meeting were given to the Auditors for the trouble they had taken in examining the Treasurer's Accounts.