Sheet music can be seen at Indiana University Sheet Music Collections:

SLUMBER BOAT
Words, Alice C. D. Riley. Music, Jessie L. Gaynor.
Chicago: Clayton F. Summy Co., 1898.

1. Baby's boat the silver moon,
Sailing in the sky,
Sailing o'er the sea of sleep,
While the clouds float by.

CHORUS: Sail, baby, sail,
Out upon that sea,
Only don't forget to sail
Back again to me.

2. Baby's fishing for a dream,
Fishing near and far.
His line a silver moonbeam is,
His bait a silver star.