When I heard the learn'd astronomer,
When the proofs, the figures, were ranged in columns before me,
When I was shown the charts and diagrams, to add, divide, and measure them,
When I sitting heard the astronomer where he lectured with much
applause in the lecture-room,
The astronomer displays his findings and results in an organized, but constrained way. Everything is neat and compact and explained cleanly, when in reality, things are never that way. Whitman’s use of the word “ranged” evokes the idea of containment and placing limits. 

When I Heard the Learnd Astronomer