Scientific Intelligence. — Natural Philosophij. S55 



upon the liquid which surrounds it, and with which it mingles. 

 There are thus (including chemical action), four causes which 

 concur in the production of the electrical effects, df which the 

 result is shewn by the galvanometer. The action of saline solu- 

 tions upon each other, or upon acids, being often one of the pre- 

 ponderating causes, when the chemical action is I'eeble, it is 

 upon its examination that M. Becquerel first enters. He then 

 gives an easy means of observing the electrical effect which re- 

 sults from the action of an acid or a liquid upon a metal, the 

 reaction of liquids not being considered. The author then ex- 

 amines the effects which take place in a voltaic element, in con- 

 sequence of the chemical action of liquids on each of the metals. 

 To appreciate these effects, he takes a glass vessel, in the inte- 

 rior of which he places two leather partitions, to retard the mix- 

 ture of the liquids contained in each of the cases. On trying 

 different liquids, it is found that the maximum of intensity of 

 the current takes place perceptibly when copper is immersed in 

 a saturated solution of nitrate of copper, and zinc in a sa- 

 turated solution of sulphate of zinc. From this he deduces 

 a process for having in a voltaic couple electrical effects which 

 exhibit very little variation during an hour. Several voltaic 

 couples united lead to the same result. The electrical forces 

 developed in the chemical action of liquids have been employed 

 by M. Becquerel to produce combinations. Carbon, which is 

 one of the most extensively diffused simple bodies in nature, 

 and which performs a conspicuous part in its phenomena, is 

 first submitted to investigation. The property which this body 

 possesses of combining in various proportions with hydrogen, has 

 enabled him to form chlorurets and insoluble metallic iodurets. 

 If, for example, some hydrochloric acid, a plate of silver and car- 

 bon, are put into a tube, the silver being positive, the pole attracts 

 the chlorine, with which it forms chloruret of silver, which crys- 

 tallizes in octahedrons ; the hydrogen prevails over the carbon, 

 combines with it, and the gaseous product is disengaged. To 

 form double chlorurets and double iodurets, a tube is taken, 

 bent in the form of the letter V, and filled at its lower part with 

 sand or clay impregnated with water. A solution of nitrate of 

 copper is poured into one of the branches, and into the other 

 a solution of an alkaline or earthy iiydrochlorate. The commu- 

 nication is then established with a plate of copper. The end 



