There are three kinds of primary batteries in general use in the British Postal Telegraph Department, viz., the Daniell, the bichromate, and the Leclanche.
The Daniell type consists of a teak trough divided into five cells by slate partitions coated with marine glue.
In diameter, to a total resistance of zoo ohms. The actual current required to work the instrument is 3.3 milliamperes (equivalent approximately to the current given by 1 Daniell cell through 3300 ohms), but in practice a current of to milliamperes is allowed.
The electrolysis is generally conducted with platinum electrodes, of which the cathode takes the form of a piece of foil bent into a cylindrical form, the necessary current being generated by one or more Daniell cells.
As an example of a fairly constant cell we may take that of Daniell, which consists of the electrical arrangement - zinc zinc sulphate solution copper sulphate solution copper, - the two solutions being usually separated by a pot of porous earthenware.
Thus in the Daniell cell the dissolution of copper as well as of zinc would increase the loss in available energy.
Considered thermodynamically, voltaic cells must be divided into reversible and non-reversible systems. If the slow processes of diffusion be ignored, the Daniell cell already described may be taken as a type of a reversible cell.
It is now evident that the electromotive force of an ordinary chemical cell such as that of Daniell depends on the concentration of the solutions as well as on the nature of the metals.
Notwithstanding its rugged and mountainous character, Pisidia contained in ancient times several considerable towns, the ruins of which have been brought to light by the researches of recent travellers (Arundell, Hamilton, Daniell, G.
In cases when great accuracy is not required, a Daniell cell can be used as a standard of electromotive force.
Long, the initial source of electrification being a single Daniell cell.
JOHN FREDERIC DANIELL (1790-1845), English chemist and physicist, was born in London on the 12th of March 1790, and in 1831 became the first professor of chemistry at the newly founded King's College, London.
His name is best known for his invention of the Daniell cell (Phil.