Royal Institution of Great Britain, 185 



passed along the spiral from the copper plate to the zinc, or, in 

 other words, that, as far as the metallic conductor was concerned, 

 the copper plate acted as the positive side of an electric jar, and the 

 zinc as the negative side. Mr. Ritchie thought that considerable 

 ambiguity still prevails with regard to the poles of the compound 

 battery, since the extreme plates of zinc and copper are superfluous, 

 and derange the regular order of the three elements when the circle 

 is completed. Thus, when the circle is completed in the common 

 trough, the arrangement of the elements is, zinc, copper, and fluid- 

 zinc, copper, and fluid . zinc, copper ; zinc, copper: whereas 



by simply striking out the extreme plates, the regular order of the 

 elements is restored. The lecturer then dwelt particularly on the 

 fac{, observed by Oersted, that the magnetic needle invariably 

 places itself at right angles to the conducting wire, provided the 

 needle be rendered astatic. He then shewed, by the ingenious 

 contrivance of M. Ampere, the direction which the needle invariably 

 assumes, when acted on by a voltaic current. Mr. Ritchie con- 

 cluded, by exhibiting the Electro-magnetic Telegraph, proposed by 

 Ampere, by means of which, rapid communication might be carried 

 on between distant towns in every state of the weather. 



Let a number of thick copper rods or strong wires be laid below 

 the public road between distant towns, and let them be connected 

 with the wires of delicate galvanometers in each of the towns. If 

 a number of letters, with the usual abbreviations, be applied to 

 those needles, they will, of course, be put in motion by the passage 

 of powerful voltaic currents. By observing the needles which are 

 successively put in motion in one of the towns by a current sent 

 along the proper wire from the other, it is obvious that a news- 

 paper, printing in London, may be printed at the same time in 

 Edinburgh and other remote towns. As experiments have not yet 

 been made with thick wires of sufficient length, and batteries of in- 

 tense powers, the lecturer concluded, by observing, that, in the 

 present state of the inquiry, we cannot pronounce, with absolute 

 certainty, with regard to the success of this ingenious project. 



Arthur Kett Barclay, Esq., M.R.I., who has lately returned from 

 the northern parts of the continent, placed a magnificent specimen 

 of native platina, from the Ural mountains, upon the library-table. 

 It was in one piece, and weighed upwards of three-quarters of a 

 pound. It had evidently been rubbed or beaten over all parts of 

 the surface. 



