Add 1 hour to time

[Jeff Honken]

I know there must be a simple way to do this but it's excaping me.  I
just need to add one hour to a time that I've set.  Here's the code that
doesn't work but it's the general idea:

on mouseUp
  put "10:00 AM" into currentTime
  put "currentTime + 1:00" into FutureTime
  answer FutureTime
end mouseUp

Can someone show me how to set a time into a variable and add an hour to
it.  Thanks,  Jeff