178 APPENDIX TO MEMOIR OF PELTIER. 



II. — Static electeicitt. 



Difference of static and dynamic electricity. — Electricity may present itself in 

 two distinct conditions ; it may be in repose or in movement. In the first case 

 it is said to be in a static, in the second in a dynamic, state. The phenomena 

 wliicli it produces in these two cases are very ditrerent. 



This distinction is to he found in all treatises on physics ; but no author has 

 insisted so much as Peltier on the difference — on the almost constant opposition, 

 indeed, which exists lictween the phenomena produced by static electricity and 

 those produced by dynamic electricity; by electricity in repose or in movement.* 



Static electricity, says Peltier, is double; each of its forms is collected, con- 

 trolled, and maintained separately. They do not become manifest except in 

 this state of insulation and of separation. They may be preserved thus sepa- 

 rated by means of insulating bodies, and their action then is as enduring as their 

 insulation. Static electricity is accumulated at the surface ; its effects reduce 

 themselves to the phenomena of attraction and repulsion. When two bodies 

 are charged with the same electricity they separate from one another ; when 

 charged with contrary electricities they approach one another, &c. 



Dynamic electricity exhibits constantly opposite properties. It is not double; 

 it cannot be collected, coerced, or preserved. To have a constant dynamic effect, 

 it is necessary that the cause itself should act in a constant manner. It seeks 

 not the surface ; on the contrary, it is propagated through the interior of bodies 

 and has relations only w-ith ponderable quantities of matter, l^ike currents 

 attract one another ; unlike currents repel one another. Finally, dynamic elec- 

 tricity has an extreme diversity of action; it alters the tem])erature of bodies, 

 vaporizes or decomposes them, magnetizes iron and steel, causes deviation of the 

 magnetic needle, &c. 



The two orders of phenomena, static and d^aiamic, are rarely coexistent ; it is 

 only when the current has ceased, through a forcible interruption, that a static 

 effect appears ; so, too, it is only when free course is given to the cause of the 

 static effect that the dynamic effect is reproduced ; but the two effects never are 

 and never can be simultaneously produced by the san)e portion of electricity. 

 When these two effects make their appearance at the same time, as happens in 

 the case of an insufficient conductor, the portion of electricity which passes pro- 

 duces only dynamic effects, and the portion of electricity arrested produces only 

 static effects. 



Ilelation of static and dynamic actions. — Peltier had measured the extent of 

 the electric phenomena, both static and dynamic, wdiich may be produced by the 

 oxidation of a milligram of zinc. By causing the electricity produced by a 

 given (piantity of substance to pass successively from the dynamic to the static 

 condition, and from the static to the dynamic, he found that the quantity of sub- 

 stance necessary, in order to produce the dynamic eifect of one degree of a good 

 multiplier, may yield a static effect of 7,069 degrees of the electrometer of his 

 own invention, and, moreover, that the static effects which it produces are as the 

 square of its dynamic effects ; hence the quantity of oxidized substance which 

 doubles a dynamic effect, quadruples the static effect which s])rings frum it.t 



Electric capacity of the metals. — Peltier first demonstrated that the metals 

 have not equal capacities for receiving the same static electricity from a constant 

 source; thus, zinc takes and retains more positive than negative electricity, while 

 the contrary takes place with cojiper. Gold is likewise more apt than silver 

 and platina to become charged with positive electricity.^ 



* See Annales de CIcimie et de Physique, 1838, t. 67, p. 422: a memoir of Peltier on the 

 quantities of dynamic and static action produced by the oxidation of a milligramme of zinc, 

 See also the article Galvanism of the Dictionnaire Univers. d' Hit^toirc Nuturttle. 



t Annalrs de Cliimie et de Physique, 1838 ; memoir before cited. 



t Comptes-rendus de r Academic dcs Sciences, 1835, t. 1, pp. 360 and 470. 



