The standard size consists of a rectangular trough of ebonite or wood, 9 1/2 in. by 11 in. by 13 3/4 in., divided into 6 cells by means of ebonite partitions. In each cell is firmly fixed a porous pot having a capacity of about 1 qt., and fitted with a short ebonite pipe; all these pipes are secured to an ebonite pipe running the full length of the battery, and fitted with an ebonite tap and a gauge-glass or level. It will be seen that by this means all the porous pots are connected together, and can be quickly and easily emptied, when the solution is exhausted, by merely opening the tap. In a like manner all the outside cells are connected together and fitted with a tap. The general arrrangement has been made with a view to reducing the time required for charging or emptying to a minimum, and permits of the battery being charged or emptied in a few minutes without the usual disagreeable labour attending these operations.

Two stoneware barrels, each having a capacity of 6 gal., are placed on a shelf above the battery level and fitted with stoneware taps, to which are attached lengths of rubber tubing. One of the barrels is filled with the exciting liquid, 1 of sulphuric acid to 18 of water, the other with the new depolariser. When it is required to charge the battery, the tubes are fixed on to the ebonite battery taps, and the solutions allowed to flow until they rise to the marked point on the levels; the battery is then ready for immediate work. When the solutions are spent, the battery taps are opened and the solutions allowed to flow away.

The elements are zinc and carbon; each cell contains two sheets of zinc placed in the outside cell, one on each side of the porous pot. The carbon plate is placed inside the porous pot with the depolariser. The carbon heads are well coppered and securely fixed in tinned brass clamps, into which solder is run, thereby making a perfect and luting contact, and doing away with the constant trouble usually given by carbon contacts. The zincs are specially amalgamated, and if the current is not allowed to exceed the maximum for which the battery is designed, they do not require reamalgamating.

The charge of depolarising liquid for the 6-cell battery of the dimensions given is 11 pints; the voltage in open circuit 13 volts, and the working current for the best results 15 amperes; this current is maintained for 7 hours per charge. During this time the current is very nearly constant, rising for the first 2-3 hours, then remaining constant for about 3 hours, and finally dropping slowly to the starting-point; these variations are very small. The total energy given oat per charge is about 1300 watt hours, of which 750- 800 watt hours are expended in the external circuit, or say, 230 watt hours per quart of solution. If, after the 7 hours' work, the current is reduced, by reducing the number of lamps in circuit to about 10 amperes, a further run of 3-4 hours can be obtained, giving a total energy per quart of depolariser of Two of the above batteries will run ten 8 c-p. incandescent lamps, or sixteen 5 c.p. lamps for 7 hours, and if, as indicated above, the number of lamps is reduced, a further run of 3-4 hours can be obtained.

It is specially suited for small installations, motive power for boats, lathes, dental machinery, Ac.

Bella. 7b ring while door it being opened. - (a) Fig. 101. A is a spring of hard brass about 1/16 in. thick and 1 in. wide, fixed on to architrave moulding of door frame; B is a similar spring fixed on to door; the connections are shown, C being short helix where the door hinges, to prevent the wire breaking; D, bell ;E, battery; F, switch to. cut off when not wanted.

(b) Fig. 105. A is a piece of wood or metal screwed on to door. D is made of wooden bar let into the door frame at top right-hand comer, supports a wooden rod E which carries the brnss small clock spring bent, and then hardened at a right angle; a bole is drilled (or punched) while soft, and the, spring, well brightened, is screwed on to the block ss shown. When the door is opened, A presses the spring B against the screw C, and when returning to its, place A presses B away from C. Thus the bell will only ring when door is being opened. The block may be 6 in. long, and A may be made of steel spring, which gives longer contact.

Weymersch Battery 50091Bell to ring by opening door.

Bell to ring by opening door.