J. C. Hoadley & Co.

15.  To guard against injury to the cylinder or piston, from overheating, the following apparatus, referred to in Section 11, is introduced.

From the chamber of the slide starting-valve at the base of the dome, a small pipe extends down nearly to the crown-sheet of the firebox, so that its lower end is always immersed in the water. A small cock, inch diameter, is inserted in this pipe, with its plug parallel to the axis of the boiler; and a rod coupled to this plug extends through a stuffing-box in the fire-box casing above the fire-door, and below the rod of the slide starting-valve. A small handle, like a gimlet handle, on this rod, serves to turn it by, and to indicate the state of the -inch cock. When the handle is vertical, the cock is open, and a jet of water forced through the -inch pipe enters the valve-chamber under the whole difference of pressure caused by the action of the governor-valve. Entering the steam-pipe at a higher temperature than that of the steam inside, it speedily evaporates, so that no water appeared at the cylinder petcocks when this injection-cock was opened for experiment.

When the handle is horizontal, the cock is shut, and no water enters the steam-pipe.

*16. With considerable effort, a brisk fire, good draught, and the engine at rest, the cylinder was in one instance intentionally heated, in the course of an hour, to such a degree that a squeaking noise was produced by the friction of the piston on starting.

This noise almost instantly ceased on opening the injection-cock; and, after keeping it open three or four minutes, giving time for the current of steam to reduce slightly the temperature of the cylinder, the engine ran smoothly with the injection-cock permanently closed.

In this manner, by introducing a slight degree of moisture into the steam-pipe and cylinder, when required for lubrication, superheated steam may be safely and conveniently used almost all the while, and all danger of excessive heating obviated.

17.  The steam-gauge (a Bourdon gauge, made by the American Steam-Gauge Company, Boston), is arranged to indicate either the pressure in the steam-dome or that in the steam-pipe below the governor-valve, as required; thus showing at any time the extent of 'throttling' produced by the governor. This is managed by a two-way cock, admitting steam to the pressure-gauge from either one of two pipes, one entering the dome and passing down to the starting valve chamber, and the other opening into the dome itself.

18.  The safety-valve is placed at the top of a chamber on the side of the fire-box casing, and held down by a spiral spring pressed upon by the base of the whistle, which serves as a set-screw to regulate the pressure required to lift the safety-valve. When lifted, the escaping steam blows the whistle. To blow the whistle, the safety-valve is lifted by the whistle-lever. To the chamber above mentioned are attached the glass water-gauge, three gauge-cocks, and the steam-pressure gauge; so that all the indications required about the state of water and steam in the boiler are combined in this apparatus, which might be called with some propriety, a Pantaphane.