The common answer for this is that it is a joke. He was singing that because he was singing a few bars. This is a wordplay on the word bar of soap, and also on the fact that bars in music are <span>a segment of time corresponding to a specific number of </span><span>beats, so it's a pun actually.</span>
The danger and difficulty in escaping from slavery are hard to imagine. Most slaves were illiterate and had no money and few, if any, possessions. The colour of their skin made them easy targets during the daylight for those who would hunt them down—often with the help of bloodhounds—and return them to their owners.
It started with the battle of lexington and concord
I believe that it would be steam.
