The song appeared in "Harriet, the Moses of her People," published by Sarah Bradford in 1886, (first title- "Scenes in the Life of Harriet Tubman") describing the life of Harriet Tubman, pp. 49-50 (of the 1900 reprint). Said to have been sung by Harriet Tubman.
Dialect is removed from the version given by Jerry, above, e. g., "De hounds," etc. No tune is given.
The chorus is varied after each verse:

Cho. 1
Farewell, ole master, don't think hard of me,
I'm traveling on to Canada, where all de slaves are free.

Cho. 2
Oh, righteous father, wilt thou not pity me,
And help me on th Canada, where all de slaves are free.

Cho. 3
Farewell, ole Master, don't think hard of me,
I'm traveling on to Canada, where all de slaves are free.

The first edition of the book made $1200, which was given to Harriet Tubman to lift a mortgage on her little farmstead in New York, which she had purchased with the help of Secy. Seward (of Alaska purchase fame).

Another fragmentary song from Harriet Tubman (same source):

Glory to God and Jesus too,
One more soul got safe.

Glory to God in the highest,
Glory to God and Jesus too,
For all these souls now safe.

Another fragment, same source- said to have sung by Harriet Tubman as some 800 slaves were rowed out in the Combahee River, and loaded aboard Yankee gunboats commanded by Col. Montgomery, to be carried to Beaufort. Tubman, during the War, was a spy and information gatherer.

Of all the whole creation in the East or in the west,
The glorious Yankee nation is the greatest and the best.
Come along! Come along! Don't be alarmed,
Uncle Sam is rich enough to give you all a farm.
Response- Glory!