I have that album. The song "Let It Grow" is utilizing 'slide guitar'. While similar to a Dobro in the way it is tuned,
it is a regular 6-string guitar (acoustic or electric...in this case, electric) that is tuned to the root note or chord.
The player uses a glass or metal tube to slide along the strings in order to achieve that sound.
Interestingly, this song exudes George Harrison influence. He took slide guitar (ie "Cloud Nine") to a whole
new level. His work with The Traveling Wilbury's is very similar to the way Clapton has adapted slide for this
song.