The page may be zoomed out, with the page on display try resetting the zoom. To do that in the View menu select Zoom, and then select Reset.

For more details see the page zoom and text zoom articles.

Hi Tony, Thanks a bunch,it worked prefectly. Colin

Please mark this thread as SOLVED.

This thread was not solved until now. My FF Google results showed tiny fonts while the left and right columns showed normal sizes. View > Zoom > Reset did not work. There is another thread under this heading where it was suggested that Tools > Options > Content will allow you to set font sizes. The correct solution is to choose a Minimum Font Size. Mine had None set. Just remember that different font types show different sizes for the same setting.