Sporadic bad weather had been reported in the Atlantic throughout October, although the Dei Gratia encountered none and her journey across the ocean in November was uneventful. Just short of a month later after leaving port, on December 4, 1872 (some reports give December 5, due to a lack of standard time zones in the 19th century), at approximately 13:00,[clarification needed] the helmsman of the Dei Gratia, John Johnson, sighted a ship about five miles off their port bow through his spyglass. The position of the Dei Gratia was approximately 38°20′N 17°15′W / 38.333°N 17.25°W / 38.333; -17.25Coordinates: 38°20′N 17°15′W / 38.333°N 17.25°W / 38.333; -17.25, some 600 miles west of Portugal. Johnson's keen, experienced eyes detected almost at once that there was something strangely wrong with the other vessel. She was yawing slightly, and her sails did not look right, being slightly torn. Johnson alerted the second officer of the vessel, John Wright, who had a look and had the same feelings about it, and then they informed the captain. As they moved closer to the other ship, they saw that it was the Mary Celeste. Captain David Morehouse was confused as to why the Mary Celeste was not already in Italy by that point, as she had a seven day head start on his own ship. According to the account given by the crew of the Dei Gratia, they got up to 400 yards from the Mary Celeste and cautiously observed her for two hours, having been under full sail, yet sailing erratically on a starboard tack, and slowly heading toward the Strait of Gibraltar. They concluded that she was drifting after seeing nobody at the wheel or even on deck, though she was flying no distress signals.
Oliver Deveau, the chief mate of the Dei Gratia went across to the Mary Celeste. He checked the pumps which were in good order. They returned sometime later visibly stirred and unnerved. According to his report, Deveau did not find a soul on board, and reported that "the whole ship was a thoroughly wet mess". There was only one operational pump, two apparently having being disassembled, with a lot of water between decks and three and a half feet (1.1 m) of water in the hold. The ship however was not sinking and the vessel was seaworthy.
All of the ship's papers, except the captain's logbook, were missing. The forehatch and the lazarette were both open, although the main hatch was sealed. The clock was not functioning and the compass was destroyed, and the sextant and marine chronometer were missing. The only lifeboat of the Mary Celeste, a yawl, which had been located above the main hatch, was also missing. The peak halyard, used to hoist the main sail, had disappeared. A rope, perhaps the peak halyard, was found tied to the ship very strongly and the other end, very frayed, was trailing in the water behind the ship.
Popular stories of untouched breakfasts with still-warm cups of tea on the cabin table, are nonsense and most likely originated with fictionalized accounts of the incident, including one by Sir Arthur Conan Doyle. At the inquiry Oliver Devreau stated that he saw no preparations for eating and there was nothing to eat or drink in the cabin.
Devreau went back to his ship and reported to the captain, then with a party of two men Charles Augustus Anderson and Charles Lund, returned to the Mary Celeste.
The cargo of 1,701 barrels of alcohol Devreay reported, was in good order. However, when it was eventually unloaded in Genoa, nine barrels were found to be empty.