120 ANNUAL OF SCIENTIFIC DISCOVERY. 



scquently detached itself from the ball; the tube becoming instantly after- 

 wards filled with the most brilliant strata. 



There can be no doubt that the superior effulgence of the bands obtained 

 with this tube is due to the character of its electrodes; the bands are the 

 transported matter of these electrodes. May not this be the case with other 

 electrodes? There appears to be no uniform flow in nature; we cannot get 

 cither air or water through an orifice in a uniform stream; the friction 

 nirainst the orifice is overcome by starts, and the jet issues in pulsations. 

 Let a lighted candle be quickly passed through the air; the flame will break 

 itself into a beaded line in virtue of a similar intermittent action, and it may 

 be made to sing, so regular are the pulses produced by its passage. Analogy 

 miii'ht lead us to suppose that the electricity overcomes the resistance at the 

 surface of its electrode in a similar manner, escaping from it in tremors ; 

 the matter which it carries along with it being broken up into strata, as 

 liquid vein is broken into drops. 



ON THE ORIGIN OF ATMOSPHERIC ELECTRICITY. 



It is well known that the earth is, relatively to the air, negatively electri- 

 fied. If a bar of polished metal be held horizontally, no electrical phenom- 

 ena are manifested, but when it is turned to a vertical direction at once the 

 lower extremity becomes positively electrified, and the upper negatively. 

 This takes place evidently by induction. So in a thunder-storm. The air 

 at the surface, becoming abnormally heated and moist, comes to be in a state 

 of tottering equilibrium, in which state the slightest disturbance will throw 

 it rolling over and over, and, rising into colder regions, it condenses and falls 

 as rain. The rising column, like the bar before mentioned, becomes at bot- 

 tom charged with positive electricity, and at the top with negative; and the 

 thunder-cloud becomes, in fact, two, one above the other, which Mr. Wise, 

 the aeronaut, has often seen and described. Between these, filled with oppo- 

 site electricities, a gigantic spark passes, which is the forked lightning. 

 Thus the conclusion is that atmospheric electricity is due to induction from, 

 the earth. Prof. Henry. 



/ 



NEW SECONDARY TILE OF GREAT IWYER. BY M. G. TLANTE. 



Jacobi proposed recently the use of secondary electric currents for tele- 

 graphic purposes, and Plante" had suggested the substitution of electrodes of 

 lead for those of platinum in these batteries. A more extended study has 

 convinced him of their use. He states that a battery with electrodes of lead 

 has two and a half times the electro-motive force of one with electrodes of 

 platinized platinum, and six times as great as that of one with ordinary plati- 

 num. This great power arises from the powerful affinity which peroxide of 

 lead has for hydrogen, a fact first noticed by De la Rive. The secondary 

 battery which he recommends has the following construction: It con- 

 si-ts of nine elements, presenting a total surface of ten square metres. Each 

 clement is formed of two large lead plates, rolled into a spiral, and separated 

 by coarse cloth, and immersed in water acidulated with one-tenth sulphuric, 

 acid. The kind of current used to excite this battery depends on the 

 manner in which the secondary couples are arranged. If they are arranged 

 so as to give three elements of triple surface, live small Bunsen's cells, the 

 zincs of which are immersed to a depth of seven centimetres, arc sufficient 



