Cells, Bunsen, 56_a_; bichromate of potash, 51; closed circuit, 50; dry, 58; Edison-Lelande, 59; electricity generated by, Chap. III.; Fuller, 55; Gonda, 57; gravity, 56; Grenet, 52; Leclanché, 57; open circuit, 50; plates and poles of, 45_a_; polarization of, 48; simple, 45, 49; single-fluid, 49; two-fluid, 49; various voltaic, Chap. IV. Central stations, 170; a word about, Chap. XXVI. Chain lightning, 19. Chafing-dishes, electrical, 147. Charging condensers, 15. Chemical action, and electricity, 81. Chemical effects of electric current, Chap. VII. Chemical meters, 78. Church organs, pumped by motors, 162. Circuits, electric, 50; for lamps, 144. Cleats, porcelain, 141; wooden, 141. Clocks, automatic electric, 172. Closed circuit cells, 50. Coils, induction, and how they work, Chap. XIII.; induction, construction of, 104; method of joining, 98; primary and secondary, 103; resistance, 69; rotation of, 95; of transformers, 135. Collectors on dynamos, 129. Commutators, 129. Compasses, magnetic, 31. Compound, magnets, 28; wound dynamo, 131. Condensation of static electricity, 15. Condensers, 15; for induction coils, 104. Conductors, and insulators, 4, 138. Conduits, electric, 140. Connections, electrical, 60; for telegraph lines, 111. Controllers, for automobiles, 169; for electric cars, 165. Copper sulphate, effects of current on, 82; formula of, 79. Copper voltameters, 75. Cords, adjustable for lamps, 151. Coulomb, the, 76. Crater of hot carbons, 152. Crookes tubes, 156, 158. Current, detectors, 93; direction of in cell, 46; from magnet and coil, 100; from two coils, 102; induced, 127; of induction coils, 105; interrupters, automatic, 104, 115; local, 47; primary and secondary, 102; transformation of, Chap. XVIII.; transmission of, 134. Currents, and motion, 160; how distributed for use, Chap. XIX. Current strength, 71; measurement of, 73; unit of, 72. Cylinder electric machines, 9. Daniell cell, 56. D'Arsonval galvanometer, 73. Declination, 41. Decorative incandescent lamps, 151. Dental, lamps, 151; outfits, 176. Detectors, astatic, 94; current, 93. Diamagnetic bodies, 29. Diaphragm for telephones, 120. Dip, of magnetic needle, 42. Direct current, 129, 130. Direction of current in cell, 46. Discharging condensers, 15. Disruptive discharges, 154. Distribution of currents for use, Chap. XIX. Door opener, electric, 175. Dots and dashes, 110. Drill press, run by motor, 162. Dry cells, 58.