119, _120_; signalling, 225; slot, 226. Electroplating, 185, _186_. Electro-magnets, 117. Endolymph, 272. Engines, compound, 59; donkey, 68; double-cylinder, 47; internal-combustion, 87, 95; reciprocating, 44. Escapement of timepieces, 416; cylinder, _420_; lever, 421, _422_. Ether, 270. Eustachian tube, 276. Eye, human, 246, _247_; self-accommodation of, 248. Expansive working of the valley in the 'Philosophical Transactions' for 1877, I add the following experiment: A rectangle, x Y (p. 331), 22 inches by 3 inches; 12 oz, 2 inches by 6 inches. 3rd observation 2 feet 10 inches. 4th observation 3 feet long and.