MAWSON & SWAN, 



COMBINED INSTRUMENTS. 



Combining in one instrument both Voltaic and Induction Batteries, 



Combined Battery, consisting of 30 Voltaic Cells and an Induction 

 Instrument, in mahogany French polished case, with brass 

 handle, lock and key, hooks and eyes, graduating dial, battery 

 break, commutator of the poles, till for sponges, insulated con- 

 ducting wires, a pair of cylindrical rheophores, pair of disc 

 rheophores, wire brush, sponges, &c. * - -.1414 o 

 Do. do. 40 Cells and Induction Instrument 16 16 o 



Do. do. 50 do. do. do. 18180 



A variety of other Patterns, and every improved form, added to stock as 

 introduced. 



FOR CONTINUOUS CURRENT. 



The Leclanche Medical Battery is strongly recommended as the 

 most constant form at present made ; it requires also no atten- 

 tion, is always ready for use, and emits no unpleasant odour, 

 and will, if fairly treated, continue in action for two years or more 

 without any attention, when it can be recharged at a small cost. 



PRICE 



Simple Batteries 20 cells, 4 xos. ; 30 cells, 6 ; 40 cells, 7. 

 With Current Breaker 20 cells, ^5 IDS. j 30 cells, J^j los. 

 With Current Breaker, Commutator, and Pole Reverser 40 cells, 

 11 ; 50 cells, 12 los. ; 60 cells, ^"14 los. 



All the Batteries are fitted in Polished Teak or Mahogany Boxes. 



RHUMKORFF'S INTENSITY COILS, for working vacuum tubes and 

 other experimental purposes ; well-made instruments. 



Length of spark j j j- j i i 2 inches. 

 Price - - - 13 6 22 6 45 - 63 - 84 - ^7 ^8/io/- 



Larger sizes we quote for specially. 



13 and 15, Mosley-street) Neivcastle-on-Tyne. 



