DISCOURSE OF W. B. TAYLOR: NOTES. 379 



gated equally through the interior of conducting bodies, and in 

 proportion to their mass quite irrespective of the form of their 

 surfaces. Two bodies charged with the same kind of static elec- 

 tricity, exhibit mutual repulsion ; while if charged with contrary 

 kinds they exhibit mutual attraction: and by contact establish a 

 complete neutralization. Two currents of dynamic electricity, in 

 the same direction attract each other; in opposite directions repel 

 each other : the contact of their conductors produces neither divis- 

 ion nor neutralization; nor does any external communication disturb 

 the current in a closed circuit. A body charged with either kind 

 of static electricity exerts no action but attraction on a neutral 

 body ; it induces the opposite electrical state on the portion of a 

 body approached, repelling its own kind to the further extremity. 

 A current of dynamic electricity produces various inductive effects 

 on neighboring bodies, as transverse magnetization, instantaneous 

 impulses at the moment of any change, chemical actions, etc. The 

 former finds an equilibrium of its two forms in very unequal 

 degrees in different metals.* The latter finds only conducting 

 differences between the metals; and is not affected by other cur- 

 rents. The former is feeble or intense according to the extent of 

 surface on which it is accumulated; and manifests its tension by a 

 greater or less attraction or repulsion. The latter exhibits the 

 states of quantity measured by the deflection of the galvano- 

 meter, and of intensity measured by the power of overcoming 

 resistance or of traversing poor conductors." f 



Characteristically different as are the phenomena thus exhibited 

 by mechanical and chemical electricities, (to distinguish which we 

 have unfortunately no satisfactory expressions,) almost as marked 

 though in a much smaller degree, are the peculiarities of galvanism 

 itself, in what must be called its varying states of tension. And 

 for these striking differences, Ohm's celebrated law that "the 

 strength of the current is proportional to the electro-motive force 

 divided by the conducting resistance," affords no more intelligible 

 explanation than it does for the peculiar deportment of so-called 

 "static" electricity. Indeed Ohm's formula represents but a close 



* Peltier first demonstrated that the electric capacity of the metals for the 

 same kind from a constant source, is very unequal: thus zinc takes and retains 

 more positive than negative electricity, while the contrary takes place with 

 copper: so gold is more apt than silver or platina to become charged with posi- 

 tive electricity. (Comptcs Rendus, 1835, vol. i. pp. 360 and 470.) 



t Annales de Chimie et de Physique, 1838, vol. Ixvii. pp. 426-428. The title of this 

 memoir is "Experimental researches on the quantities of static and dynamic action 

 produced by the oxidation of a milligramme of zinc:" and the author arrives at 

 the conclusion that the static effects are as the squares of the dynamic effects; 

 or conversely, the dynamic as the square roots of the static, (p. 446.) 



