13. Valve for admitting steam to the jets which force air into the fire-box. 14, 14′. Throttle-valve lever. This is for opening the valve which admits steam to the cylinders. 15. Sector by which the throttle-lever is held in any desired position. 16. "Lazy-cock" handle. A "lazy-cock" is a valve which regulates the water-supply to the pumps and is worked by this handle. 17, 17′. Reverse lever. 18. Reverse-lever sector. 19, 19′, 19″. Gauge-cocks for showing the height of the water in the boiler; 19′ is a pipe for carrying away the water which escapes when the gauge-cocks are opened. 20, 20. Oil-cups for oiling the cylinders.[13] 21. Handle for working steam-valve of injector. 22. Handle for controlling water-jet of the injector. 23. Handle for working water-valve of injector. 24. Oil-can shelf. 25. Handle for air-brake valve. 26. Valve for controlling air-brake. 27. Pipe for conducting air to brakes under the cars. 28. Pipe connected with air-reservoir. 29. Pipe-connection to air-pump. 30. Handle for working a valve which admits or shuts off the air for driving-wheel brakes. 31. Valve for driving-wheel brakes. 32, 32′. Lever for moving a diaphragm in smoke-box, by which the draught is regulated. 33. Handle for raising or lowering snow-scrapers in front of truck-wheels. 34. Handle for opening cock on pump to show whether it is forcing water into the boiler. 35. Lamp to light the water-gauge, 51, 51. 36. Air-hole for admitting air to fire-box. 37. Tallow-can for oiling cylinders. 38. Oil-can. 39. Shelf for warming oil-cans. 40. Furnace door. 41. Chain for opening and closing the furnace door. 42. Handles for opening dampers on the ash-pan. 43. Lubricator for air-pump. 44. Valve for admitting steam to the chimney to blow the fire when the engine is standing still. 45. Valve for admitting steam to the train-pipes for warming the cars. 46. Valve for reducing the pressure of the steam used for heating cars. 47. Cock which admits steam to the pressure-gauge, 48. 48. Pressure-gauge which indicates the steam-pressure in heater pipes. 49. Pipe for conducting steam to the train to heat the cars. 50. Cock for water-gauge, 51. 51, 51. Glass water-gauge to indicate the height of water in the boiler. 52. Cock for blowing off impurities from the surface of the water in the boiler. Besides being impressive as a triumph of human ingenuity, there is much about the construction and working of locomotives which is picturesque. A shop where they are constructed or repaired is always of interest. An engine-house (Fig. 35) especially at night, is full of weird suggestions and food for the imagination. [Illustration: Fig. 36.--Cab End of a Locomotive and its Attachments.]