ELEOTEIOITY. 



241 



negative pole, while the elements of anhydrous 

 acid and oxygen, which answer to basic hydro- 

 gen or to metal, fly to the positive pole. Such, 

 he claims, is the fundamental action of ^ the 

 electric current. M. Bourgoin has specially 

 studied the action of the current on neutral 

 tartrate, on a mixture of tartrate and alkali, 

 and on free tartaric acid. To examine the ac- 

 tion on tartaric acid, a concentrated solution 

 of the neutral tartrate of potash is conven- 

 iently operated upon. As soon as the current 

 passes, the solution becomes alkaline at the 

 negative pole ; only a moderate disengagement 

 of gas is produced at the two poles. The prin- 

 cipal result is the formation of a white precip- 

 itate, which is slowly but continuously de- 

 posited from the positive electrode. Analysis 

 shows this substance to be wholly cream of 

 tartar. The solution at the positive pole re- 

 mains neutral during the experiment. The 

 gas evolved at the positive pole was composed 

 of carbonic acid, oxygen, carbonic oxide, and 

 nitrogen. Nearly the whole of the loss takes 

 place at the positive pole. 



The tartaric acid thus regenerated at the 

 positive pole forms, with the neutral tartrate, 

 cream of tartar; there is, however, some tar- 

 taric acid destroyed by oxidation. The action 

 of the current on a mixture of neutral tartrate 

 and alkali produces quite different results to 

 those obtained with neutral tartrate only, not- 

 withstanding that the fundamental action is 

 the same. At the positive pole a mixture of 

 carbonic acid, carbonic oxide, oxygen and hy- 

 dride of ethylen is evolved. M. Berthelot dis- 

 covered acetylen also in the sample of the gas 

 sent him by M. Bourgoin. The decomposition 

 of free tartaric acid yielded the same products 

 as the neutral tartrate, though in different pro- 

 portions. The carbonic acid is the dominant 

 product from the first ; the carbonic oxide di- 

 minishes as the experiment proceeds ; the same 

 is the case with the oxygen and nitrogen, 

 though to a less extent. Acetic acid is formed 

 at the positive pole. After the fifth day the 

 experiment had been in progress, the solution 

 in the neighborhood of the positive pole con- 

 tained a large quantity of acetic acid, which was 

 isolated as acetate of baryta. 



New Batteries. M. Cauderay has devised a 

 battery, composed of four elements, of which 

 the electro-motors consist of perfectly new car- 

 bon plates, the one being what is termed ag- 

 glomerated carbon, the other gas carbon. 

 These plates never having been previously 

 used, were, consequently, free from acids and 

 salts. The battery was connected up in the 

 ordinary manner, the carbon of one cell being 

 connected to the gas carbon of the other, and 

 so on. Immediately on being placed in action 

 the battery gave a current of 45 on a galva- 

 nometer, and rang a bell perfectly for a space of 

 about ten minutes. The intensity diminished 

 rapidly after that time; but after a rest of 

 about one hour the battery had almost recov- 

 ered its previous force. Each time that the 

 VOL. viii, 16 A 



battery was tried a rest was always sufficient 

 to restore its action ; but after each trial the 

 force became less, until, after trying it for 

 thirty-five days, it became so weak as to give 

 only 3 on the galvanometer, and at that 

 period a remarkable change took place. The 

 sign of the current altered: the current, 

 which hitherto had been passing from the ag- 

 glomerated to the gas carbon, was now pro- 

 ceeding in the opposite direction. M. Cauderay 

 states that, on the second day after the fixing 

 of the battery, he thought he remarked a strong 

 smell of gas-tar. He perceived that this smell 

 was accumulated around the last gas carbon 

 forming the positive pole of the battery. It 

 seemed to him then extremely probable that 

 the gases which diffused those smells had been 

 withdrawn from the interior of the carbons by 

 the current, to be accumulated and disengaged 

 at the positive pole, for previous to their being 

 immersed the carbon had no smell whatever. 

 The agglomerated carbon placed in the same 

 cell was covered by bands of very brilliant 

 colors, among which were Prussian blue, vio- 

 let, green, etc., arising, he supposes, from the 

 decomposition of salts, or, perhaps, from a 

 small quantity of tar contained in the gas car- 

 bon. A peculiar fact in connection with these 

 bands is, that they were precisely similar in 

 order to those of the solar spectrum the red 

 at top and the violet below, with all the inter- 

 mediate colors of the spectrum. 



M. Gr. Plante has invented a new " secondary 

 battery," as he calls it. It consists of a novel 

 and peculiar arrangement for multiplying the 

 power obtained from a weak source. In form 

 it is not unlike an ordinary condenser. There 

 is a rectangular gutta-percha vessel provided 

 with lateral grooves, and containing a series of 

 lead plates immersed in dilute sulphuric acid. 

 As in a large condenser, the odd plates are 

 joined in one series and the even plates in an- 

 other series ; to either end is attached one of 

 the poles of a weak source. Such a battery, 

 with six plates only, and a source of two small 

 nitric couples, was strong enough to create 

 temporary incandescence in a platinum wire 

 one millimetre thick and eight centimetres 

 long. By increasing the size and number of 

 the plates, more powerful calorific effects, such 

 as incandescence of iron and steel rods, may be 

 obtained by charging the battery with two or 

 three Bunsen's elements. An arrangement, 

 termed by the same inventor his " secondary 

 tension battery," produces still more remark- 

 able results. The apparatus consists of forty 

 secondary couples, each couple of lead plates 

 being in a narrow gutta-percha vessel, im* 

 mersed in dilute sulphuric acid, the pole of 

 each vessel being connected to a peculiar com- 

 mutator, so that the plates could be joined as 

 an arrangement of tension or as one of surface. 

 This battery was charged with three couples 

 of Bunsen's medium-sized battery. On apply- 

 ing the current from the secondary circuit, a 

 platinum wire, two metres long and one-quar- 



