At 1.10 p.m. on the 30th December, 1915, the s.s. _Persia_ was torpedoed without warning when 40 miles from land. The second officer, in charge on the bridge, saw the wake of an approaching torpedo on the port bow, and a moment later there was a violent explosion. This was followed by a second explosion, which, in the opinion of the chief and second officers, was caused by the bursting of a boiler. The vessel at once listed over to the port side and went down in five minutes. No boats on the starboard side could be launched owing to the list, and several on the port side were swamped, torn away, or capsized, owing to the way which was still on the ship. One port-side boat had been smashed by the explosion, another was pressed under water by the davits, as the ship rolled over to port. Only five boats got away, 213 of the crew and 120 passengers losing their lives, through the explosion or by drowning. Four over-loaded boats were adrift for 30 hours before being picked up by a mine-sweeper. The fifth boat, which had been damaged, capsized several times, and contained only 11 survivors when picked up at 8 p.m. on the 31st by another steamer.
The upshot of the _Persia_ affair was that Count Bernstorff submitted an official memorandum to the United States Government, stating that Germany proposed to conduct her submarine campaign according to the rules of international law. The Germans admitted that it was possible that a German submarine sank the _Persia_, and promised that, if this were so, the guilty captain would be punished.
The _Euphrates_ was a Belgium Relief ship which left Rotterdam in January, 1917, bound for Sandy Hook in ballast. She was provided with a German safe conduct at Rotterdam to cover her voyage back to the States. She flew the Belgian flag aft, and exhibited the Relief Commission's signals by day and night. In daylight these consisted of a white square flag, bearing in the centre the words "Belgian Relief Commission" in red letters, a white pennant with the same words in the centre, also in red letters, and a ball painted with red and white vertical stripes above distinguishing flags, all at the foremast. At night the words "Belgian s.s. _Euphrates_, Relief Commission, Rotterdam," brilliantly illuminated in large letters, extended from about amidships, on both sides, to the stern.