NATURAL PHILOSOPHY. 177 



attached to each element. The elements do not enter the liquid 

 when the cell is in an erect position, but action is established by 

 invertinn^ the apparatus. A battery of 95 such cells operated in 

 a most satisfactory manner. In connection with telegraphic 

 instruments it produces remarkable effects, and in medical use 

 occasions contractions that no induced current will produce. 



Manganese Battenj. — A battery, composed essentially of perox- 

 ide of manganese and a single liquid, chloride of ammonium, has 

 been recently constructed by M. Leclanche, and, according to 

 ** Les Mondes," has been already somewhat extensively adopted, 

 or, at least, taken on trial by several telegraph companies on the 

 Continent. It has been long known that peroxide of manganese 

 possesses an electric conductivity similar to that of metals. The 

 author uses only the natural crystalline peroxide of the purest 

 quality. This is broken up and placed in a porous vessel, where 

 it surrounds a carbon plate, forming the positive pole of the bat- 

 tery ; the negative plate outside the porous vessel is simply a thick 

 rod of zinc ; the liquid which bathes both plates is a concentrated 

 solution of sal-ammoniac. It appears to be a very constant fornt 

 of battery, and exceedingly economical. 



Battery of Iron and Sulphuric Acid. — The cylindrical glass ves- 

 sel holds a cylinder of v/rought or cast iron, within which is placed 

 a prism of carbon, and water acidulated with oil of vitriol. Two 

 pairs are sufficient for working an ordinary electrical bell. These 

 elements are very cheap, and, if the liquid becomes concentrated, 

 it may be used in another battery, where the cylinder of iron is 

 replaced by one of zinc. 



Battery of Zinc and Ferrous Sulphate. — By introducing a zinc 

 plate or cylinder into a concentrated solution of ferrous sulphate 

 it will dissolve under disengagement of h3'drogen, and hydrated 

 ferric oxide will be precipitated ; carbon being used as before with- 

 in the zinc. Two of these pairs will last two days for a common 

 house-bell. 



Copper and Zinc. — The bottom of a wide-mouthed bottle is 

 covered by a disk of copper, to which is attached a copper wire, 

 and which is covered first with dry, powdery carbonate of copper, 

 and then with a disk of felt or cloth. The remaining space within 

 the bottle is filled with sand, the whole covered by a zinc disk 

 with another copper wire. The contents are then moistened by a 

 solution of muriate of ammonia (20 per cent.) in water, and the 

 flask hermetically closed. On closing the current, the salt, before 

 unaffected, will be decomposed into muriatic acid, which passes 

 to the zinc-pole, and into ammonia, by which latter the carbonate 

 of copper is rendered soluble ; and by its decomposition this latter 

 produces a secondary current equal in intensity to a pair of 

 Daniell's. This instrument, therefore, consumes its material only 

 as long as it is in activity, and it has of late been prepared for use 

 on several French railroads. 



Balsamo'^s Battery. — M. Balsamo has presented to the French 

 Academy a battery, both elements of which consist of iron, the 

 one being immersed in a solution of chloride of calcium, the other 

 in diluted sulphuric acid, — the two solutions being separated by 



