356 
CORRESPONDENCE. 
—___—_ 
THE DYNAMICAL THEORY OF ELECTRICITY. 
To the Editor of the TECHNOLOGIST. 
S1r,—Since I sent you a short notice ofa fact in thermo- 
electricity, I have had under revision my chapter on 
organic electricity, and I have been forcibly impressed by 
the harmony existing between obvious deductions from the 
dynamical theory, and some recently observed physiological 
results. 
The physiological effects by acting causes incidental to 
transmission of a continuous voltaic current through a mus- 
culomotor nerve, are of a complex character; they are 
universally acknowledged to be manifested only at the 
moments of closing and opening the circuit, but are modi- 
fied by the influence of the current, during its prolonged 
continuous passage in the portion of nerve-tissue included 
in the circuit. 
In order to interpret correctly all its observed physiolo- 
gical effects, it becomes necessary to consider carefully the 
dynamical consequences of the passage of a continuous suc- 
cession of electric waves, here assumed to constitute a 
voltaic current, they must comprise three distinct phases: 
First, the momentary passage of the molecules of the con- 
ductor from a state of rest to a state of motion; secondly, 
the indefinite continuance of a molecular motion; and 
thirdly, the return of the moving molecules to a state of 
rest. 
The first phase will be accompanied by a rush, or a sud- 
den impulse of increased potential in the direction of the 
current, because there must be a condensation or accumu- 
lation of motion, in consequence of the inertia of the mole- 
cules at rest, opposing the transmission of the wave; this 
may be termed the initial current. During the second 
phase there will be (supposing the potential of the current 
to remain constant for the time) continuous and uniform 
wave motion. During the third phase, the excitation of 
motion ceasing, the ws viva of the moving particles will 
accumulate motion towards the termination of the conduc- 
tor, whence a reflex motion may be expected to be propa- 
gated, (as in the case of a wave travelling from the hand 
along a stretched cord, which reaching the fixed end, is re- 
flected back again), giving rise toa momentary ‘terminal 
