tallow-cup

from The Century Dictionary.

• noun Tallow is much less used for lubrication than before the use of mineral oils became general. A goblet-shaped cup of cast-brass, with a cock in the part corresponding to the goblet-stem, was screwed into the cylinder-cover. When steam was shut off, and the engine running by its inertia, the cock could be opened, and on the aspiration stroke of the piston the pressure below the cock would be enough less than that of the atmosphere to cause the latter to press the tallow, softened by heat, down into the cylinder. In condensing-engines the lubrication could be done when the engine had steam on, provided the cock was opened on the exhaust stroke on that side of the piston.
• noun A lubricating device for a journal-box, etc., in which tallow is melted by the heat of steam, and caused to run down upon the parts to be lubricated.