A Home-Made Edison Battery 



THE good points of the Edison 

 battery are great constancy, very 

 low internal resistance and freedom 

 from local action when on open-circuit. 

 Following are the particulars of a home- 

 made Edison battery which can be built 

 very cheaply and which will give every 

 satisfaction. 



The battery consists of a 

 perforated copper pipe A 

 (Fig. i), containing black 

 oxide of copper as the positive 

 element, and a zinc cylinder C 

 as the negative element. 



The exciting liquid is a 25- 

 per cent solution of caustic 

 potash in water, which means 

 a solution of one pound of 

 caustic potash to three pounds 

 of water. The containing jar 

 is represented by D; E is a 

 cover which excludes dust and 

 from which the copper pipe 

 and zinc cylinder are sus- 

 pended by means of the brackets F and 

 G. The two binding posts H are con- 

 nected to A and C respectively. 



The battery here described, which will 

 give a constant current of 20 

 amperes, uses a containing- 

 jar 6 ins. by 10 ins. In build- 

 ing this battery it will be best 

 to obtain the containing jars 

 first, since all the other di- / / /!_ 

 mensions are fixed by the 

 size of the jar. 



First procure a copper tube 

 of 3-in. bore and 834 ins. long, 

 about 1/32 in. thick. To 

 perforate the tube, slip it 

 over a stick of wood a little 

 smaller in diameter than the 

 tube; punch the holes through with a 

 |)unch or a nail. The holes shoulif be 

 about 3/8 in. in diameter. 



Cut a wooden disk 3 ins. in diameter 

 and about '^s '"• thick. Drill a ]/i-w. 

 tlrain-liole in it and soak it for about 

 fifteen minutes in molten i)araffin wax. 

 Tlien fix the disk with shellac solution 

 in the bottom end of the copper tube. 



Procure some coi)per strip about I in. 

 by y^ in. Bend 3 lugs, G, as shown, and 

 rivet tluni to the cojjper cylinder. Tlie 



Fig. 1. Dimen- 

 sions and parts of 

 the battery 



Fig. 2. Proper po- 

 sition of the lugs on 

 the cyHnders 



lugs must be equally spaced (Fig. 2), 

 showing the drilling in the top cover E, 

 where A' represents the holes for support- 

 ing A , and Y the holes for supporting C. 

 The copper cylinder is now completed 

 and we take next the zinc cylinder in 

 hand. This should be made from rolled 

 zinc and not from cast ma- 

 " terial. The best plan is to 

 buy a cylinder of the size re- 

 ([uircd as you are sure to get 

 the right material. Prefera- 

 bly the zinc should be well 

 amalgamated as it lasts much 

 longer. Three lugs made 

 from the same strip as used 

 f(3r the copper c\linfler should 

 then be riveted to the zinc 

 c\ Under. They must be again 

 equally spaced as shown in 

 Fig. 2. 



One lug on each copper and 

 zinc cylinder should then be 

 soldered to the respective 

 cylinder in addition to the riveting, so as 

 to make as good a connection as possible. 

 These two lugs are tlie ones subsequently 

 connected with the l)inding posts H. 



The cover E is now the last 

 part to be made. It is made 

 from good hardwood to the 

 dimensions given and should 

 be a snug fit in the containing 

 jar. Six holes J^ in. in 

 diameter are then drilled in 

 the co\er and spaced as siiown 

 in the figure, so as to avoid a 

 short-circuit between the lugs 

 (/ of the cojiper cylinder and 

 till- lugs Fof the zinc cylinder. 

 The cover must now be 

 soaked in molten paraffin wax 

 for at least fifteen minutes. Then ob- 

 tain two large liinding posts H, ten 

 3/16-in. nuts, 6 washers for the same 

 and 6 steel rods, screwed 3/16 in. 

 f)n each end, one end to take the bind- 

 ing posts or nut on top of the co\er 

 E and tlie other end to take the nut 

 below the brackets F and G. 



In assembling the battery, first fill the 

 copper c\'linder with black oxiile of 

 copper and boll the cylinder to the 

 co\er Fl. V\\ tlie zinc cNlinder C to the 



Ti^ 



