Creation is a hymn tune composed by William Billings.
Billings included Creation in his final collection, The Continental Harmony (published in 1794).
In 2002, historian of science Edward B. Davis (co-editor of The Works of Robert Boyle) discovered that Watts based the second stanza on a meditation by the famous chemist Robert Boyle.
In that text, from Occasional Reflections Upon Several Subjects (1665), Boyle reflected on an illness from which he had recovered, noting the great complexity of the human body and the wonder of how it all stays so well for so many years.
Strange that a harp of thousand strings Should keep in tune so long.