948 



Popular Science Monthly 



very fast for making these holes. The 

 three-series eight-parallel battery shown in 

 Hg. 2 requires i6 of the U-shaped pieces 

 and also i6 pieces of the short L-shaped 

 length. 



The filling for the lead tubes is made up 

 of a thick mixture of red lead and dilute 



•->«i' 



This diagram 

 shows the ar- 

 rangement of 

 the cells and 

 lead fillers for 

 use where the 

 battery is to be 

 charged with a 

 current from 

 other batteries 



sulphuric acid — one part acid to two parts 

 water. Be careful in making the dilute 

 solution of acid. Always pour a small 

 quantity of the acid in the water and stir 

 vigorously. Never add water to the acid. 

 The paste mixture should be about as 

 thick as putty. As there must be different 

 mixtures in each leg of the lead tube the 

 other mixture is made up in 

 the same manner except that 

 yellow lead — litharge — is 

 used instead of the red lead. 

 One leg of each tube is 

 stuffed full of the red lead 

 mixture and its mate with 

 the yellow. All of the double 

 elements are treated in a like 

 manner. In making up the 

 smaller lengths fill half their 

 number with the red lead and 

 the other half with the yel- 

 low; thus for the 24-series 

 unit there will be two of the 

 short tubes used — one filled with 

 and the other with yellow lead. 

 3-series, 8-parallel unit there will be 8 short 

 pieces filled with red lead and 8 with the 

 yellow lead. In either case force the paste 

 in so that it will be pushed out through the 



holes, then scrape ofT the excess so that it 

 presents a smooth surface. 



Before the elements are assembled they 

 must be treated for charging. One method 

 is to charge the assembled battery and 

 then discharge in the opposite direction. 

 This operation should be repeated four or 

 five times. Another way is to lay the legs 

 filled with the red lead in a strong solution 

 of chloiide of lime, or a solution of nitric 

 acid, or sulphuric acid — one part acid to 

 two parts water. Allow the elements to 

 remain in the solution until they are some- 

 what roughened. 



If the latter method is used the battery 

 is ready to assemble. This is very plainly 

 shown in the illustrations. In building up 

 the battery shown in Fig. 2 a single red 

 lead element is placed in the end test tube 

 and one leg of a yellow lead double element 

 is introduced into the same test tube, the 

 other leg being placed in the second tube. 

 Continue by using one more double element 

 and finish with a single yellow lead element. 

 This makes each tube with one positive 

 element and one negative, and one unit 

 of three cells is complete in the series. The 

 other 7 units are built up in the same 

 manner. The illustration Fig. i shows 

 plainly how the 24-cell unit is made up, 

 starting with a single element and finishing 

 with the opposite single element, the inter- 

 mediate ones being filled with the double 

 elements. 



Two binding posts are used on the 24-celI, 

 as shown. The screws are passed through 

 the frame and through a hole in the end 

 of the element. This is plainly shown in 



t»IsI«I ^ «I«»Jl^l^I 



3 



5"- 



Ty 



FOR 3-CELL UNIT 

 MAKL 16 



fORE4-CELLUNI7 

 MANE 2 



BEND IN THIS- 

 MANNER 



FOR 3-CELL UNIT 

 MAKE 16 



FIG4 



,ir'' 



; 



DRILL FOR 

 BINDING 

 POST 



The elements are made of lead pipe cut to the right lengths, 

 bent into shape for entering the cells and drilled for holes. 

 Each tube has one positive and one negative element 



red lead 

 For the 



B, Fig. I. For the 3-series, 8-parallel unit 

 there are required 16 binding posts, two for 

 each unit.. The posts are fastened in the 

 same manner as for the 24-cell unit. The 

 reason 16 posts are needed is that the cells 

 must be connected in parallel for charging 



