284 



ELECTRICITY. 



is moving. Sometimes negative electricity may 

 be observed during a shower ; but this is al- 

 ways due to a more powerful shower farther 

 off. These conclusions have been supported 

 by means of telegraphic communication with 

 neighboring districts. It appears, then, that, 

 except when the moisture of the air is being 

 condensed, there is no unusual development 

 of electricity. 



Electricity of Plants. Dr. Ranke, of Bava- 

 ria, has investigated the electricity of plants, 

 taking, for his experiments, the petioles of the 

 Rheum undulatum, and other plants, which, 

 on account of their parallel fibrous structure, 

 offered peculiar advantages for examination. 

 The apparatus used in measuring the currents 

 was similar to that employed by Du Bois Ray- 

 mond, in his researches into animal electricity. 

 Du Bois Raymond had demonstrated that, 

 while the life of animal tissues continues, elec- 

 trical currents pass through the organs accord- 

 ing to definite laws, and in correspondence 

 with the various phenomena of life. It was 

 reasonable to expect that in plant organisms 

 something analogous would be found to oc- 



Du Bois Kaymond named an imaginary cross-sec- 

 tion, in the centre of a cylindrical piece of animal tis- 

 ue, the equator, and a line through the middle of the 

 cross-section, the axis. When ne applied the elec- 

 trodes to two points of the cross-section, which were 

 symmetrical to the axis, or to two points of the longitu- 

 dinal section, which were symmetrical to the equa- 

 tor, there was no current. But, if the points were 

 not thus symmetrical, there was a current:; in the 

 one case, the point more distant from the axis being 

 positive to the nearer ; in the other the point nearer 

 to the equator being positive to the more distant. 

 In plants, something quite analogous is observed, 

 the dissection of the currents, however (named like 

 those of Du Bois Kaymond, the weak currents), be- 

 ing reversed. Thus, in the case of plants, where 

 twounsymmetrical points are taken in the cross-sec- 

 tion, that which is farther from the axis is negative 

 to that which is nearer. And of two unsymmetrical 

 points on the longitudinal section, that which is 

 nearer to the equator is negative to that which is 

 more distant. 



Further, in pieces cut of a rhombic form, currents 

 were observed analogous to those Du Bois Raymond 

 observed in similarly-cut muscles, from the acute to 

 the obtuse angles ; but, in the plants, the direction 

 was reversedc 



Another point of correspondence between animal 

 and plant electricity is ? that the currents only appear 

 during the life of the tissue. The reaction of tissues 

 which show animal electricity is always more or less 

 alkaline, or neutral. After separation of the tissue 

 from the living body, an acid reaction is gradually 

 produced, and, when this has taken place, the elec- 

 tromotive action disappears. The living tissue of 

 plants, on the other hand, is generally more or less 

 acid, and, on the death of the tissue, an alkaline re- 

 action is produced, and, then, also, the electromotive 

 action is extinguished. 



Dr. Ranke experimented with a large number of 

 plants besides Rheum, and found, in each case, the 

 same laws of electromotive act' on to hold good where 

 the fibres were arranged parallel. 



Experiments were also made with pieces in which 

 the fibres were not parallel, as in the case of certain 

 roots ; and the normal electric currents were met 

 with, if the shape of the root did not depart very 

 much from the cylindrical, was not very conical. If, 



for the point of application of an electrode, on the 

 longitudinal section, a part of the root was chosen at 

 which the tissue branched off, this acted as a cross- 

 section, and the current might be reversed. The 

 same remark applies to stems. 



Dr. Ranke observes, in the conclusion of his paper, 

 that the similarity which has been established be- 

 tween animal .and plant electricity, warrants us in 

 applying to the latter, with certain modificationsj Du 

 Bois Raymond's molecular hypothesis of animal 

 electricity. We may suppose the interior of electro- 

 motive parts of plants filled with small peripolar 

 molecules embedded in a conducting substance, the 

 axes of these (joining the poles of each molecule) be- 

 ing parallel to the axis of that part of the plant con- 

 taining them. The theory of animal electromotors 

 supposes each of the molecules to have two negative 

 polar zones, and one positive equatorial. The law 

 of plant electricity requires, on the other hand, for 

 each of the molecules, two positive polar zones and 

 one negative equatorial. 



New Forms of Battery. A process of accu- 

 mulating and transforming the electricity of 

 the voltaic pile, by means of secondary, bat- 

 teries, has been discovered by M. Plante. The 

 secondary batteries are formed of two sheets 

 of lead rolled into a spiral, and separated from 

 each other by India-rubber bands, instead of 

 the coarse cloth used in former experiments. 

 These spirals are then immersed in glass vases 

 filled with acidulated water, the extremities 

 of the two plates being connected to binding 

 screws. Twenty of the elements thus arranged 

 are placed in two rows of ten each, and their 

 terminals connected to the springs of a commu- 

 tator so adjusted that the elements could be con- 

 nected up for surface or quantity when charg- 

 ing, and in series for intensity when discharg- 

 ing. The battery power used to charge the 

 apparatus is from two to three Bunsen ele- 

 ments. When the commutator is turned so 

 that the elements are joined up for quantity, 

 the battery develops in each element an elec- 

 tromotive force equal to about one and a half 

 time that of a single Bunsen or Grove's ele- 

 ment ; and, when connected up in series, for 

 intensity, an electromotive force equal to thir- 

 ty Bunsens could be produced, affording a cur- 

 rent sufficiently powerful to fuse platinum 

 wire, and make the electric light. 



M. Bouman, of Holland, has effected an im- 

 provement in the Lelanche battery, rendering 

 it much more constant. It consists of a plate 

 of carbon and an amalgamated zinc rod, cov- 

 ered with woollen cloth, placed vertically in a 

 glass jar which is two-thirds filled with the 

 mixture employed for this description of bat- 

 tery, namely, coarsely-powdered carbon and 

 manganic peroxide. The difficulty hitherto, 

 found in obtaining and preserving a good con- 

 tact between the carbon pole and its conduct- 

 ing wire has been overcome, by cutting a slit 

 in the carbon, and inserting a platinum wire. 

 Mr. Higgs, by arranging a series of small-sized 

 carbon and zinc cylinders, in alternate series, 

 in one vessel, has been enabled to obtain, in a 

 very small compass, a battery giving an elec- 

 tromotive force equal to ten Daniell's elements. 



The following arrangement of a copper and 



