[MILLER] CHEMICAL LABORATORY RESEARCHES 57 



(14) The Alkali Treatme^jt of Storage Battery Separators 

 By J. H. Ratcliffe 



The separators (sheets of wood, 6 X 6 X 5/32 inches) were boiled 

 for 27 hours in a 2.5% solution of caustic soda and samples removed 

 every hour. The maximum permeability of the wood to salt solutions 

 was reached on boiling for 3 to 4 hours, after which it decreased. 

 The loss of weight of the wood, and the loss of caustic from the solution 

 reached a maximum on boiling for 5 to 7 hours, after which it remained 

 constant. The following is the order of permeability, after treatment, 

 of the woods tested; the numbers are proportional to the diffusion 

 constants: Basswood 63, B.C. cypress 45, poplar 35, elm 33, southern 

 cypress 29, B.C. cedar 24, Port Orford cedar 24. Elm is much the 

 strongest mechanically of the woods examined. 



(Under direction of Professor J. T. Burt-Gerrans) 



(15) The Use of Glycerine in Making up Battery Plates 

 By W. D. Stalker 



Negatives.- — A dry mixture of litharge with one per cent, lamp 

 black (graph itized carbon is not so good) was worked to a paste with 

 a solution containing water 66%, sulphuric acid 17%, glycerine 17%, 

 by volume; about 11 c.c. liquid to 70 g powder. This was pasted 

 on automobile grids of the lattice type, 4.75 X 2.5 X 0.125 inches, and 

 dried at room temperature for five days between wooden boards under 

 pressure. The plates were then formed for 24 hours with 0.25 amp., 

 which sulphated them badly; this was followed by 39 hours at 0.5 

 amp. The negatives so formed showed complete conversion (voltage 

 against cadmium) ; their current efficiency- — ^viz., the ratio of ampere- 

 hours output (8 hours to fall from 2.1 to 1.8 volts measured on open 

 circuit) to input (under the same conditions)- — was 76%; and their 

 weight was 91.5 g. per ampere hour. When they were made in the 

 same way without glycerine the efficiency was 82% but the weight 

 was 233 g. per ampere hour. 



Positives.— A mixture of red lead 75%, litharge 25%, and lamp- 

 black 0.3% was pasted with the same glycerine acid solution (about 

 12 c.c. liquid to 65 g. drj' mixture). The plates were dried in air for 

 17 days, but no change in weight occurred after the fifth day. They 



