THE SCIENTIFIC WORK OF GEORGE SIMON OHM. 258 
This communication was but the precursor of that classic work so 
frequently referred to: “The Galvanic Battery Treated Mathematic- 
ally.” This he produced in the quiet of a much-needed vacation, and 
published in May, 1827. 
In the introduction to this article he says his aim has been *to 
deduce in connected sequence and from a few principles those elee- 
trical phenomena which are comprehended under the epithet galvanic; 
the purpose is accomplished if the variety of facts is subordinated to 
the simplicity of comprehension.” Indeed he accomplished his purpose 
most completely. He extended to electrical conduction the ideas of 
Laplace, Poisson, and especially Fourier on the conduction of heat, and 
evolved the laws of the electric current with the mathematical means 
which those investigators had created for their own purposes. This 
thoughtful theory of Ohm stands to-day unshaken,—a compactly con- 
structed whole. In order to bring it into unison with the present views 
concerning electricity it is only necessary to remark that what Ohm 
calls “electroscopic force” or “tension” is nothing but electrical 
potential. 
The Laplace-Poisson equation, which formed the basis of Ohm’s de- 
ductions, shows indeed that in a conductor carrying constant electric 
currents, as well as in one in electric equilibrium, the free electricity is 
all distributed on the surface. The surface layer, however, in the case 
of the currents shows a different distribution from that in the condition 
of equilibrium. Ohm, on the contrary, assumed that the free electricity 
was spread over the whole cross-section of the conductor carrying the 
current. This assumption called forth many contradictions, because it 
was So foreign to the nature of electricity. By removing this contra- 
diction newer views, without changing in the least Ohim’s formula or 
conclusions, have only served to establish the theory all the more firmly. 
The subsequent extension of his theory, by its application to conductors 
of two and three dimensions, was an immediate generalization of his 
method of treatment which Ohm himself foresaw; also, the enunciation 
in that well digested work of Ohm’s on the non-constant or charging 
and discharging currents, stands to-day in unchanged correctness. 
As has already been emphasized, the first discovery of Ohm’s law as 
to the intensity of current is not contained in that master investiga- - 
tion. The law previously discovered and proven by experiment served 
only as the touchstone for the theory of which it appeared to be a 
necessary consequent. But the brilliancy of this theoretical accom- 
plishment threw his previous tedious work of empirical investigation so 
into the shade that it is partly conceivable how the belief arose that 
Ohm mathematically deduced his law from debatable hypotheses. 
At first Ohm received no recognition from even this work. It 
received no attention in many circles; from many sides came sharp 
criticism; from only a few genuine approval. His hopes of being able 
