Describe the first ghost in A Christmas Carol.

The first ghost represents the
past, and flickers in and out while glowing but is neither old nor young while neither male nor
female.

When Jacob Marley comes to visit his old partner, he
tells him he will be visited by three ghosts on three nights.  His word is true.  Scrooge
awakens to find a strange looking ghost in his house: the ghost of the past.  The ghost is
described as having bare skin, with bare feet and arms.  He or she is neither old nor young, and
dressed in white.  The contradictions continue in the fact that he or she has both winter holly
and spring flowers. 

But the strangest thing about it was,
that from the crown of its head there sprung a bright clear jet of light, by which all this was
visible; and which was doubtless the occasion of its using, in its duller moments, a great
extinguisher for a cap .... (Ch. 2)

The ghost is kind
most of the time, explaining to Scrooge that he is going to show Scrooge the past, but not just
any pastScrooges past.  The past that The Ghost of Christmas Past shows Scrooge begins with his
childhood and progresses to the more recent past.  Some of the visions are hard for Scrooge to
see.  Sometimes the ghost goads Scrooge, but almost mostly gently. 

He felt the Spirit's glance, and stopped.

What is the matter?
asked the Ghost.

Nothing particular, said Scrooge.

Something, I think? the Ghost insisted. (Ch. 2)

The ghost seems to be able to see into Scrooges thoughts, and know when he is feeling
something.  He watches him, and leverages those emotions into helping Scrooge see how he affects
the people in his life.  These feelings are crucial to Scrooges development into a better
person, and the other ghosts will use them to continue his growth.

At the end
of the chapter, Scrooge finally can't take it anymore.  He has seen Belle leave him, and then
seen her with her family.  He extinguishes the ghost because he can't take the idea that he
could have had a family, when he ended up alone instead.  Scrooge is finally realizing that all
of the money in the world means nothing if you have no one to share it
with.