40 MAWSON & SWAN, 



Magnetic Needles, with brass centre 



Inches long 23469 

 Price each 1/6 1/6 1/9 1/9 2/6 

 Stand for above, i/- and 1/6 

 Ditto, Single, with Agate centres 



Inch i^_ 234 

 Price 3 /- 4 /- 5 /- 6/- ^ 

 Star Shape and circular discs of sheet iron, the set, 2/6 

 Steel Wires, for temporary magnets, per doz., 6d. 

 Set to Illustrate the leading principles of Magnetism, consisting of 

 one pair bar magnets, horse-shoe magnet, magnetic needle on 

 mahogany stand, dip needle on mahogany stand, soft iron 

 bars, &c, to show induction, electro-magnet, Oersted's experi- 

 ment, in neat black box, i TOS. 



TELEPHONES AND MICROPHONES. 



* d. 



Bell's Patent Telephone, the pair price on application 

 Electric Call Bells for above, with key and switch com- 

 bined, and two 2 cell batteries, the two sets 3 o o 



Ditto, with terminals and brass-work nickel-plated ... 3 10 o 



Battery boxes for the above batteries o 6 o 



13 and 15, Mosley-streeti Newcastle-on-Tyne. 



