i 4 MAWSON & SWAN, 



Plates for Machines, of patent plate, hole drilled through centre and 

 edges polished. If over -inch thick and with square holes, an 

 extra price will be charged. 



Inches 9 12 15 18 24 diam. 

 Price 6/6 9/- 14!- 2o/- 33/- each. 

 Ebonite Discs for Electrical Machines 



-J -inch thick 12 15 18 inch diam. 

 Price - - 6/9 9/3 12/9 each. 

 -J-inch thick 21 24 30 36 inch diam, 

 Price - - 28/9 35/- 5o/- yo/- each. 



Ebonite Discs for Electrophorous Plates 



i-inch thick 12 15 18 21 . 24 30 36 in. diam. 



Price 9/6 13/9 ig/- 26/6 31/6 49/- 657- each. 



Glass Rod, for the insulating supports, 1/4 per Ib. 

 Glass Handles, for dischargers, each i/- and 1/6 

 Pith Balls, per doz., (jd. 



large size, coloured, per doz., 2/- 

 Tin Foil, per Ib., 2/6 and 3/6 

 Wood Caps, pair and handle for cylinder machines, 2/6 



GALVANIC APPARATUS. 



BATTERIES. 



Bichromate Batteries. Small size, in glass jar, 2/6 and 3/6 



Bottle Form : single element signifies two carbon and 

 one movable zinc plate; double element signifies 

 three carbon and two movable zinc plates. 



Capacity - \ \ i 2 3 4 8 pints. 



Price, single ) ~, 



element ) 4/9 7/ ~ 9/ ~ I2/6 I4/ ~ l6 /' 3 '" each> 



Double 2o/- 23/- 38;- ,, 



Very useful Form, consisting of a number of elements, 

 each element composed of one carbon and one zinc 

 plate, each 2| in. by i in., fitted on to a wood bar, 

 so that they may be readily removed from the ex- 



citing liquid which is contained in glass cells, the 



FIG. 87. whole mounted in a simple wood frame. 



Number 2468 elements. 



~5/6 ^ 12/6 i5/- 



The same with windlass arrangement to withdraw the plates, 

 eight elements, 18/6 



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



