By cool Siloam's shady fountain [rill]. Bp. R. Heber. [Epiphany.] In its original form as "By cool Siloam's shady fountain" this hymn was given in the April No. of the Christian Observer, 1812. It was subsequently rewritten in C.M. as "By cool Siloam's shady rill,” and published in his posthumous Hymns, &c, 1827, in 6 stanzas of 4 lines, for the 1st Sunday after the Epiphany. From the Hymns, it has passed into a great number of hymnals both in Great Britain and America, sometimes in full, and again with the omission of one or more stanzas, and is most popular as a children's hymn. Authorized text in Stevenson's Hymns for Church & Home, 1873.
-- John Julian, Dictionary of Hymnology (1907)