As the resistance of the earth is inversely proportional to the
diameter of the plates, the zero resistance can also be reached by
dividing a plate _ad infinitum_. As the parts of the plate may be
brought quite close to each other without perceptibly interfering with
the action, a _network_ has finally been reached by a division carried
very far, yet limited, and by connecting the parts with one another by
conducting cylinders.
If we seek to determine what forms of ground conductors are efficient
and economical under given conditions, we shall have to begin by
informing ourselves as to the choice of material to be used for the
electrode, and shall then have to ascertain whether putting it in the
ground will or will not necessitate much outlay. The most suitable
material is copper, which may be used with advantage, in that it lasts
pretty well underground, and that the facility which it may be worked
permits of easily giving it more appropriate forms than those that can
be obtained with cast iron, which is of itself less costly.
If the burying in the ground requires little or no labor, as when
there exist ponds, rivers, and wells, or subterranean strata of water
near the surface of the earth, elongated forms of conductors will be
employed, such as the solid or hollow cylinder, the wire, the ribbon,
the narrow ring, and the network. Plates approaching a square or
circular shape are not advantageous.
Pages:
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107