1 86 Mr. G. J. Knox on the Direction and Propagation 
phsenomena of the light and heat developed ; or whether we 
adopt the gross conception of the passage of a fluid ; still it is 
important to determine if the electric force passes along the 
surface of the interposed substance, or through the interior of 
its mass. 
Dr. Faraday^ has shown that water will convey a feeble 
current of electricity, without undergoing electrolyzation. To 
determine whether, under such circumstances, it will convey 
an electrical current along its surface or through its substance, 
a glass tube, ten feet long, and half an inch internal diameter, 
bent in the centre twice at right angles, was filled with distilled 
water. Two copper wires, tw^enty feet long, having platina 
wires soldered to their extremities, were inserted in barometer 
tubes of six feet in length, the platina wires being sealed in 
the tubes within half an inch of their extremities. The other 
ends of the copper wires were connected with a delicate gal- 
vanometer, and a constant battery of successively one, two, 
four, &c., pair of elements. 
On immersing the platina wires in the liquid, their relative 
distances from each other should decrease if the current passes 
through the water, but should increase if it passes along the 
surface, the deflexion of the galvanometer indicating the path. 
With one pair of elements there was no deflexion of the gal- 
vanometer ; with two pair of elements there was a slight de- 
flexion visible through a lens, which increased slightly on im- 
mersing the platina wires in the liquid. With four pair of 
elements, a deflexion of two degrees took place when the pla- 
tina wires were on the surface of the water ; a deflexion of 
four degrees when they were immersed to the bottom of the 
tubes. As the number of alternations in the battery increased, 
so did proportionably the comparative deflexions of the gal- 
vanometer; the experiments proving that water, w'hether un- 
dergoing electrolization or not, conveys an electric current 
through its substance^ and not along its surface^ and that the 
decomposition of the water is an eflect produced by the pas- 
sage of the electricity when of sufficient intensity, and not the 
necessary consequence of its passage. 
A similar experiment having been tried with phosphorus 
melted under spirits of wine, (being a non-conductor,) it was 
found to obey the same law with water; that is, to convey the 
current through its substancef. 
To determine whether the metals followed the same law, I 
suspended from the top of the new patent shot tower at Wa- 
Scries VIII. (970.) 
f It was unnecessary to try similar experiments with the analogous 
bodies, sulphur, selenium, and iodine. 
