One source, three titles:

“SCOTLAND
Soon, the Hutchinsons grouped themselves, as if by some irresistible attraction, and sang piece after piece, to the rapture of their hearers. Those who had heard them sing “The Cot where We were Born,” "The Ohio Boatman,” and “Excelsior,” may conceive something of our delight. And, of all things to be doing, they were teaching us to play “Fox and Geese” on the green below. They themselves played with great humor; and in the midst of our fun, I saw that all the servants of the house were looking on from the corner of the terrace, and not a few laborers from outside the gate.

ENGLAND
...On one occasion we were at his concert and agreed to sing on the chorus of one of his songs. We were behind a screen, out of sight of the audience, and when we struck into the chorus of the “Boatmen of the Ohio,” it seemed as if the house would come down….”

AMERICAN SONGS
...In London Mrs. Charles Dickens became their friend and invited them on one occasion to make a morning call at her house for the express purpose of singing to her father, William Hogarth, who was a musical critic of considerable repute and influence. When the Hutchinsons arrived at the appointed morning, and were introduced to a particularly cold and very serious old gentleman who seated himself stiffly at the farther end of the room, evidently prepared for the worst, their hearts misgave them. Without much reflection they struck up the “Ohio Boatman's Song.” and went through it so successfully that the stern censor at the other end of the parlor literally flew to shake them, individually, by the hand, and to assure them he has never before listened to such delicious harmony.”
[Story of the Hutchinsons (tribe of Jesse), Vol.I-III, Hutchinson, 1896]