162 ANNUAL OF SCIENTIFIC DISCOVERY. 



tery consists of a glass or stone ware cup, at the bottom of which there is a 

 plate of non-amalgamated zinc communicating without by means of a con- 

 ducting strip. Above the plate of zinc there is a spiral formed of a rolled 

 copper plate having an attachment for making connections. A solution of 

 sulphate of potash covers entirely a plate of zinc, and wets to a certain 

 height the plate of copper. Immediately on making the connections be- 

 tween the copper and zinc, an electric current id established which continues 

 constant for several weeks. 



The inventor of this battery is an Italian, Francesco Selmi, Professor of 

 Chemistry in the University of Turin. The novel and important point of 

 it is the triple contact, viz., between the sulphate of potash and zinc, the sul- 

 phate of potash and copper, and between the copper and the air. Professor 

 Selmi has observed that there is a great advantage in this contact of the air 

 with the copper immersed in the sulphate of potash, finding that the electric 

 current is sensibly weakened when the copper is wet throughout. 



Jedlik's Improved Battery. At the last meeting of the German Asso- 

 ciation for the Promotion of Science, Professor Jedlik explained a modifica- 

 tion of Professor Bunscn's battery, made by him, with the assistance of 

 MM. de Csapo and Hammer. The septa of the cells in this modified bat- 

 tery are made of Professor Schonbein's paper, wbich may easily be repaired 

 with collodion, and opposes little resistance to the passage of the galvanic 

 current. The first experiments were made in 1844, with a one-celled, wood- 

 framed Grove's battery. Afterwards Professor Jedlik succeeded in prepar- 

 ing a mixture of sulphur, cinnabar (or oxide of iron), and asbestos, of suf- 

 ficient soliditv, and which sufficicntlv resisted the action of nitric acid. A 



fc ' / 



battery of one hundred elements, constructed on Professor Jedlik's plan, 

 although much damaged by transport, was exhibited at Paris in the summer 

 of 1855. When still unimpaired, forty of these elements gave, with char- 

 coal tops at the ends of the polar wires, a light equal in intensity to the 

 united flames of 3,500 common candles. 



TELEGRAPHIC MEMORANDA. 



At the meeting of German naturalists at Vienna, last September, M. 

 Ginti showed that one telegraphic circuit will affect another which may hap- 

 pen to be near it, though the latter be altogether unconnected with the bat- 

 tery. Pass a current through the first, and the second, as demonstrated by 

 the galvanometer, is visibly affected in some as yet unexplained way 

 through the earth. 



Improvement in House's Telegraph. An improvement, known as Bnine's 

 Printing Telegraph, has been effected on House's instrument. The main 

 parts of House's machines are type-wheels, which are made to revolve alike 

 at the different stations, so that when they arc all stopped at the same in- 

 stant by breaking the current, the same letter is, at every place, in front of 

 the instrument. Sometimes one wheel gets in advance of the others, and 

 remains so until put back by the operator. This getting out of register is 

 obviated in the new improvement, by giving the type-wheels a vibrating mo- 



