Can BP plug the Gulf gusher

the nation remained transfixed by a busted oil well spewing millions of gallons of crude into the Gulf of Mexico, BP offered few details on its latest bid to plug the worst oil spill in U.S. history and scientists suggested any progress was incremental at best.

BP PLC engineers may not know until at least Sunday if the "top kill" fix was a success, and progress was difficult to measure from BP's "spillcam" of mud, gas and oil billowing from the seafloor. Americans have been hypnotized as they watched for any sign of success, which experts said didn't appear to be overwhelming.

Scientists say the images may offer clues to whether BP is getting the upper hand in its struggle to contain the oil, said Tony Wood, director of the National Spill Control School at Texas A&M University in Corpus Christi. If the stuff coming out of the pipe is jet black, it is mostly oil and BP is losing. If it is whitish, it is mostly gas and BP is also losing.

If it is muddy brown, as it was much of Friday, that may be a sign that BP is starting to win, he said. That "may in fact mean that there's mud coming up and mud coming down as well," which is better than oil coming out, Wood said.