This artifact is a silver plated steel cup made by the International Silver Company for The Panama Line. This is an early purser's cup with a semicircular tab soldered to the outer edge so that the purser could grip the cup between his thumb and index finger. I believe that this cup was used to collect tips from the passengers. This cup is heavy. It is made out of thick steel and it is silver plated. The underside has the following engraved lettering " The Panama Line ; International Silver Co ; Silver Soldered " There is also a serial or model number: 05070A There are also two manufacturing marks on the underside near the lettering. One mark has the capital letters " I S " (for International Silver?). The other mark looks like a ship's propeller with four blades enclosed in a square frame. It was difficult to take photos of the writing, but I did my best and the photo is shown below. This cup is in used condition with surface scratches as expected, but there are no dings or other major damage.