and on a Battery with invariable Currents. 363 



branches weighed each 0«'"'*3385{= 5*0775 grs.). After forty- 

 eight hours these wires weighed 0»""'36 ( = 5'4« grs:) : they 

 had therefore gained in weight 0^*02i5(= -3225 gr.). The 

 intensity of the current which produced this effect was repre- 

 sented by 5 milligrs. (= '077 gr.). The intensity of the cur- 

 rent being diminished by one half, the quantity of copper re- 

 duced in tbrty-eight hours was found equal to 0*01, that is, to 

 half the quantity reduced in the preceding experiment. 



The same wire and the same solutions were submitted du- 

 ring forty-eight hours to the action of a current which coun*- 

 terbalanced 3 milligrs. (= '0462 gr.) : the quantity of copper 

 obtained was 0'"'012. Now, if the quantities of copper re- 

 duced in the two experiments be compared, they are found 

 to be exactly proportional to the intensities of the current. 

 Several experiments of the same kind were made with solu- 

 tions of nitrate of silver by varying the density of these so- 

 lutions and the intensity of the current. The quantities of 

 metal reduced were exactly proportional to the variations of 

 the current, the source being constant; the constancy of the 

 source being an indispensable condition. 



These results follow from the observations of Mr. Faraday. 

 But between his results and those which I have just stated 

 there is this difference, that he has disregarded the absolute 

 intensity of the current, whilst I take it into account. We 

 shall show in another memoir the advantages derived from 

 this new element introduced into experiments connected with 

 electro-chemical researches. 



We have endeavoured to ascertain by means of the electro- 

 magnetic balance, the proportions in which the quantities of 

 reduced metal are found, when solutions of several metals are 

 subjected to the action of the same current, of a known inten- 

 sity. Three solutions, one of copper, another of silver, and 

 a third of zinc, were introduced into the circuit. These solu- 

 tions were placed in tubes of the form of a U, and each of 

 them was in contact on the negative side with a plate of pla- 

 tina, and on the positive side with a plate of the same metal 

 as that in solution. They were subjected to the action of an 

 apparatus consisting of two pairs prepared with the cylinders 

 of platina ; the following are the results obtained. 



The intensity of the currents balanced a weight of 5"^'5 

 (='0847gr.). After twenty-four hours the silver precipi- 

 tated weighed 0™*305 ; the weight of the copper precipitated 

 was 0"^'090 ; that of the zinc precipitated was 0"''0925. Now 

 if we consider the proportion of the three quantities of metal 

 precipitated, we shall find that they are proportional to the 

 atomic weights of the silver, the copper, and the zinc, inasmuch 



3A2 



