i6 



MAWSON & SWAN, 



DanielVs Batteries. Of Glass (Fig. 92), with balloon holding reserve 

 of copper solution, 5/- 



FIG. 92. 



FIG. 93. 



Meidenger Battery (Fig. 93). This element is much used on the 

 continent for electric bell and similar purposes; it is excited 

 with solution of sulphate of magnesia in outer, and sulphate of 

 copper in inner cell, and will keep in action for a long time if 

 left undisturbed. 



Height without Balloon 

 Price ------ 



J7 9 in - 



5/6" y/- each. 



Ledanche Batteries. The most useful form for Electric Bells and 

 other purposes where constancy is required, and is now also 

 much in request for medical use. The outer cell usually of 

 glass, with a zinc rod ; porous cell sealed, containing a plate of 

 carbon, with a mixture of broken carbon and peroxide of man- 

 ganese ; the exciting fluid is a solution of sal-ammoniac. 



Nos. 123 

 Cells complete 6/6 4/6 3/6 



Parts supplied separately, thus 



Charged Porous Jars 3/6 2/10 2/3 



Glass Jars - 2/2 1/3 -/ro 



Zinc Rods -/6 -/5 -/4 



Sal-ammoniac - - - - - -/4 -/3 -/3 



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



