October 17, 1884. 



SCIENCE. 



385 



is at your disposal, and nobody will interfere with 

 you. If anybody else chooses to follow my example, 

 I think they can do precisely the same thing. But 

 there are, after all, one or two other uses for second- 

 ary batteries. Now, I have been very luxurious and 

 very extravagant in carrying out this arrangement. 

 For instance: I have a little daughter who has a very 

 pretty doll-house. Her doll-house consists of six 

 rooms; and each room is well furnished, and well 

 populated with charming little dolls. It is, of course, 

 necessary that each room should be supplied with a 

 charming little electric light: so each room is sup- 

 plied with this light. Then, I have a cigarette-lighter, 

 consisting of a piece of platinum which can be ren- 

 dered red-hot by the secondary battery. The diffi- 

 culty in doing that sort of thing with the usual mode 

 of distribution is that you want the benefit of cutting 

 off a portion of your current. I interrupt a current, 

 flowing, say, six-tenths of an ampere, by putting 

 into the circuit, by a switch, a secondary cell, that di- 

 minishes the light, and sets up a counter-electro- 

 motive force of two volts for the time being. While 

 tha: cell is in the circuit, your light is a little dim; but 

 when I take from the poles of that secondary circuit 

 two wires in connection with a piece of platinum wire, 

 then the current passes through the platinum; and 

 this current is due to the two volts from the second- 

 ary cell. This piece of platinum wire is heated up 

 with a current quite sufficient for the purpose, with 

 only two volts. 



Now, there is another field in which satisfactory 

 experiments have been made with secondary cells, 

 and that is, in lighting up trains of cars by electricity. 

 This has been done on one of our railways between 

 London and Brighton. The railway company has 

 been for some months past lighting up one of its 

 express trains with secondary batteries. The dyna- 

 mo is worked by the motion of the wheel, and the 

 dynamo charges the battery during the time that 

 the train is working, and the battery is being charged 

 during the whole of that time, and the current is being 

 extracted from the battery; so that you have a light in 

 your carriages which is perfectly steady, and quite in- 

 dependent of the motion of the train. And that 

 leads me to a point which I omitted, and which led 

 me to work so hard at secondary batteries; and that 

 is, that a secondary battery renders the current pro- 

 duced by the inconstant engine and the inconstant 

 dynamo perfectly steady. 



It is a difficult thing to say, that, in making an 

 appliance of any kind, we have reached absolute per- 

 fection; but I can say this, that, when you have a 

 secondary battery inserted in the electric-light circuit 

 as a shunt (p. 388), it renders your current perfectly 

 uniform, and your light is as near perfection as it 

 can be. Supposing that your lamp requires fifty 

 volts, then you will require twenty-five cells; and I 

 should think myself that it would be quite possible 

 to make cells for this purpose that ought not to cost 

 more than five shillings a cell. You put twenty-five 

 of these in cells: the first current that goes through, 

 simply charges the lead plates ; one is coated with 

 oxide, and the other is clear; and you get a counter- 



electromotive force of fifty volts. The consequence 

 is, no current whatever passes through the second- 

 ary cell unless it has once been raised to fifty volts. 

 The whole current goes through your lamp unless 

 there is flickering of the engine. Then, if there is 

 flickering of the engine, the energy that is stored up 

 in the battery passing through the lamps makes the 

 light uniform, and in that way you get the storage 

 effect by the use of the secondary battery. 



There are certain defects that have developed them- 

 selves in these batteries, that have been gradually 

 cured. The great defect in all secondary batteries is 

 due to buckling, — a fact due to the formation of 

 peroxide upon the plate. You will find your lead 

 plate will buckle up into all kinds of positions, and 

 the two plates will come into contact. This difficulty 

 I have sought to overcome by supporting the two 

 plates by means of a plate made of paraffine-wood; 

 but the most effective arrangement that I have tried 

 is ebonite. This ebonite is furnished, stamped out 

 to the proper size, and is very light and very thin, 

 though quite equal to preventing all buckling. 



Secondary cells have not been in use long enough 

 to enable us to determine how long they will last. I 

 have had them in use for four months, with a sign of 

 but little disintegration of the positive plate. I 

 think that the plates will have to be renewed only 

 about once in every two years. Those that I have in 

 use were re-charged at the end of four months. 



The charm of the whole thing is such, and its cost 

 is so trifling, that I shall keep it in my house; and I 

 am quite sure that all those who have worked in the 

 same direction in regard to this matter of electric 

 lighting will never give it up. The electric light it- 

 self has some sort of a charm about it. Objection 

 is made to the cost of introducing it; but I have 

 protested often and often against the comparison 

 that is drawn between the cost of gas and the cost 

 of electricity. The two things are not to be com- 

 pared. When we indulge in luxuries, we don't com- 

 pare the cost of the luxuries with other things. If 

 you want fine 1834 port, you don't compare its price 

 with that of ordinary claret. If you want to in- 

 dulge in a fine pheasant, you don't compare it with 

 the old cock that crowed before Peter. So, when 

 you have a delightful luxury like electricity, you 

 don't want to compare its cost with that of gas or 

 sperm-candles, or any other mode by which life is 

 shortened and ultimately destroyed. Here we have 

 something that in the out-of-the-way houses tends 

 to lengthen life and to satisfy us, giving us some- 

 thing cool and delicious; audi say, all comparisons 

 with gas are utterly ridiculous. In reference to 

 these enterprising light-companies, they will soon 

 bring electricity to our doors; and we will all take it. 

 When people can get electricity at their doors, and 

 can get it without much cost, as indeed they can, 

 they will certainly have it. So I look upon the days 

 of gas as being numbered; but gas is a most impor- 

 tant power, and its uses are just in their infancy. 

 The days of gas as a distributer of power and heat 

 are coming. At the same time, electricity is going to 

 supply light such as we want. 



