MAWSON & SWAN, 19 



Planters Secondary Cell, large size, surface of lead about 620 square 

 inches (See Fig. 95, page 17), ;i 8s. 



Planters Secondary Cell of 20 small sized cells, with Commutator 

 to join them all in tension or quantity (Fig. 96), 12 IDS. 



THERMO PILES FOR GENERATING ELECTRICITY BY HEAT. Thermo 

 Piles of 24 pairs of bismuth and antimony, in brass frame, 

 and mounted on brass rising stand, i 55. 



Ditto 28 pairs, with silvered cone, i 123. 



Ditto 80 pairs, provided with silvered cone at each end, leather 

 caps,' and mounted on brass stand with universal movement, 



4 I2S. 



Thermo-electric pair of bismuth and antimony, V shaped, witli 

 wires for connecting it .with a galvanometer, 7/6 



Clamond's Thermo-electric Pile supplied to order. 



SUNDRIES FOR THE CONSTRUCTION 

 OF BATTERIES, &c. 



BATTERY CELLS, OUTER. Round earthenware for Bunsen's 

 4x3 8d., 6x4 i/-, 8x6 i/4 each. 



Round Glass Inches 4568 high. 

 6d. 8d. i/- 2/- each. 

 Battery Cells, flat earthenware, for Grove's or Smee's 



i/- 13 1/6 each. 



Battery Cells of various other materials, ebonite, gutta-percha, &c.. and in sizes 

 too numerous to detail. Any kind not in stock procured to order. 



Battery Cells, round porous 



Length in inches 3 4 5 6 7 8 9 10 1 1 12* 



Diameter- - - ij i if ij 2 2\ 3 



Price - - 3d. 3d. 3d. 4d. 50!. 6d. yd. 9d. 12 i/4 ea ch 



Batter)' Cells, flat porous 



Inches 4^ x 2^ x J 5x3^x1 6x4x1 7x4^x1 



Price 5d. 6d. 1/3 1/3 each. 



13 and 15, Mosley-street> Newcastle-on-Tyne* 



