129. Mainspring, invention of, 59. Compound locomotives, 62. Compound microscope, 261. Condenser, marine, 71, _72_; of Ruhmkorff coil, 121, _122_. Safety-valve, 32, _33_, 391. Sand-glasses, 411. Scissors, action of, _450_. Secondary winding of induction coil, see p. 122 Chapter V. ELECTRICAL APPARATUS. What is she charged with?" "Murder, sir," replied the procureur; "a _chef d'oeuvre_ is not _our_ intellectual.