A. It enters the lamp at the binding posts with the large hole, then to the top carbon holder, carbon, then into the electrode and holder; from there to the solenoid and back to the dynamo, leaving the lamp at the binding post with the small hole in it. The magnetism from the current while passing through the solenoid attracts magnet in a downward motion, and it in turn, by the levers on the lamp, separate the carbon from the copper, thereby forming the arc.
34. Q. Why should sandpaper be used to smooth commutator instead of emery cloth?
A. In using emery paper a piece of emery might lodge in the grooves between the commutator segments, and being a conductor of electricity, causes short. Will also get embedded in the copper and cut the brushes. Sand will not do this.
35. Q. State how you would go about to focus a lamp?
A. (1) Would adjust back of reflector so front edge of reflector would be parallel with front edge of case. (2) Adjust lamp to have point of copper electrode as near the center of reflector as possible with carbons as near the center of chimney hole as you can set them. (3) Have the locomotive on straight track. Now move the base of the lamp around until you get a parallel beam of white light straight down the center of the track, then tighten lamp down.
36. Q. If the light throws shadows upon the track, is it properly focused?
A. No.
37. Q. If the light is properly focused, that is, if the rays are leaving the reflector in parallel lines, but the light does not strike the center of the track, what should be done?
A. When the light rays are thrown out in parallel lines and they do not strike the center of the track, it denotes that the headlight case is not set straight with the engine, and the entire case on baseboard must be shifted until the shaft of light strikes the track as desired.
38. Q. What can you do to insure a good and unfailing light for the entire trip?