432 



NEGEETTI AND ZAMBRA, HOLBOEX VIADUCT, B.C., 



FIG. 1888. 



FIG. 2565. 



Each. 

 a. d. 



076 



Each. 

 s. d. 



10 6 



2 15 5 10 



2544 Callan's Cast Iron or Maynooth Batteries . . 5s. 



2545 Sets of Five and Ten Cast Iron Batteries, full size, in a 



Stout wood tray 



The Maynooth Battery is composed of a Cast Iron Cell, a rectangular Porous Pot, and a stout 

 plate of Amalgamated Zinc. The porous cell is charged with Dilute Sulphuric Acid, one part strong acid 

 to eight parts Water, and the Iron Cell with strong Nitric and Sulphuric Acids, with a Saturated Solution 

 of Nitrate of Potash in equal parts. This also is a very powerful form of battery, adapted to exhibit all 

 galvanic phenomena with great brilliancy, and suited for rough Manufacturing or Mining Purposes. 

 Professor Faraday found the efficiency and steady working of Callan's Battery much improved by using 

 equal parts of strong Nitric Acid and strong Sulphuric Acid in the Iron Cell, omitting the Solution of 

 Nitrate of Potash. 



2546 A Set of 25 Callan's or Maynooth Batteries, sufficient for producing a very 



effective Electric Light for private exhibition. 



In two strong trays 10 10 



2547 Walker's Battery is similar to Smee's arrangement; but in place of the 



Platinized Silver (or Electro Negative Plate) slabs of Gas Graphite or 

 Platinized Graphite are used, the other element being Amalgamated Zinc, 

 the battery, like Smee's, being charged with Dilute Sulphuric Acid. This 

 battery is economical and simple in use, has considerable Electro Motive 

 force, and has been found very serviceable for Railway Telegraph work. 

 Price for Walker's Battery, per cell, about as Smee's Batteries. 

 The Leclanche Cell has now superseded this battery. 



2548 Dr. Leeson's Battery is formed of a plate of Copper in a Porous Cell, 

 surrounded by a plate of zinc in a stoneware jar. The Porous Cell is charged 

 with a Solution of Bichromate of Potash, one part of Bichromate to ten parts of 

 Water, the outer jar being charged with Dilute Sulphuric Acid. Price of Dr. 

 Leeson's Batteries same as Daniell's. See page 429. 



2549 Sulphate of Lead Battery. Price per Pint Cell . . . .050 



2550 Cauterising Batteries, for Amputation, &c., supplied to 



order . . . . 6 6 to 10 10 



See also Section, Medical Instruments 



The Zinc Plates of Smee's, Grove's, Callan's, Bichromate, Leclanche and 

 Bunsen's Batteries should be examined now and then, and re-amalgamated to pre- 

 vent local action, and it is advisable to thoroughly wash with plenty of clean water 

 all batteries before putting away, after use. 



