The poem When I heard the learn'd astronomer bears the same title of its first line, so that the reader understands that it is part of a collection. The poem is in free verse and some lines are longer. Therefore it will be interesting to find out a possible reason for that. In addition, the last four lines show the regular pattern in length.

The poem is the record of a memory: the speaking voice expresses his emotions and reaction while listening to a university lecture about astronomy. At that time there was an expert "the learn'd astronomer" discussing about the universe and he resorted to difficult figures, geometrical charts and the like. The speaking voice listened but he wasn't involved very differently from the audience who expressed appreciation with "much applause".

The poet doesn't seem able to explain why, without any apparent reason, he mechanically stud up and left the lecture room, tired and sick. When outside the night seemed almost mystical moist to him and he could look at the stars in the sky in perfect silence.

A connotative analysis of the poem shows the poet's preference for an anaphoric structure which privileges the first section of the poem where all line start with an interrogative pronoun "when" and significantly grow longer to convey the sense of gradual boredom of the speaking voice whose head is full "with proofs, figures, columns, charts and diagrams". Also he is asked to continuously make calculation ("to add,  divide and measure") in typical scientific approach to the study of the universe. All the poet's word choice in the first part relies on long vowel sounds to create an atmosphere of distance, the distance the speaker fills from the lecture. Indeed he "heard" and " was shown all the lecture data"; the use of perception verbs and the passive voice together with the considerable frequency of infinitive verbs add to somebody who just set and heard. He didn't act, neither  he interacted with the lecture. To tell the truth, he didn't at all feel  part of the mass uploading the lecture but he felt totally different ("I sitting heard - he lectured"), estranged from that context. Line length underlines such bored attitude and paves the way for the next section when the speaking voice felt free living the lecture room and outside "by myself" that is alone, he enjoyed "the perfect silence of the stars" and the mystical moist of the night. In both cases the alliteration of "m" and "s" adds to what he considers the suitable way to study the universe with his stars. This is a very different approach from the learn'd astronomer.