Original: An early report on "The International Radio-Telegraphic Convention" in the January 12, 1907 Electrical World stated that "Vessels in distress use the special signal, SOS, repeated at short intervals."
Simplified: An early report on "The International Radio-Telegraphic Convention" in the January 12, 1907 Electrical World said that "Vessels in distress use the special signal, SOS, repeated at short intervals."