When I heard the Learn?d Astronomer

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 the diagrams, to add, divide, and measure them;

When I, sitting, heard the astronomer, where he lectured with much applause in the lecture-room,

How soon, unaccountable, I became tired and sick;

Till rising and gliding out, I wander?d off by myself,

In the mystical moist night-air, and from time to time,

Look?d up in perfect silence at the stars. —Walt Whitman —When I heard the Learn?d Astronomer (Bartleby)

I never noticed the “unaccountable” pun in the fifth line.