Continuing to slide for the third straight day, the Bombay Stock Exchange benchmark Sensex on Thursday fell by another 104 points in early trade following weak trends in the overseas bourses. The 30-share Sensex, which had lost over 166 points in the past two sessions, dipped 104 points to 17,370 in opening trade.The wide-based National Stock Exchange index Nifty dipped below 5,200 points to trade 30.20 points down at 5,191.50. The Hong Kong's Hang Seng index was down 0.99 per cent in the morning trade today, while the US Dow Jones Industrial Average had closed 1.14 per cent lower on Wednesday.