TEXTUAL ANALYSIS

The poem When I Heard The Learn'd Astronomer bears the same title of its first line, so that the reader understands that is it 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 a 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 it was not involved, very differently from the audience who expressed appreciation with "much applause".
The poet does not 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 to him and he could look at 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 lines start with the interrogative pronoun "When" and significantly grow longer to convey the sense of gradual boredom of the speaking voice who's head is full with "proofs", "figures", "columns", "charts", and "diagrams". Also he is asked to continuously make calculations, "to add", "divide", and "measure", in a typical scientifical 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 feels from the lectured. Indeed he "heard" and "was shown" all the lecture data; the use of perception verbs and passive voice together with the considerable frequency of infinite verbs add to somebody who just set and heard.
He did not act, neither did he interact with the lecture.
To tell the truth, he did not at all feel part of the mass applauding the lectured but he felt totally different ("I sitting heard" - "he lectured"), estranged from that contest.
Line length underlines such bored attitude and paves the way for the next section when the speaking voice felt free learning the lecture room and outside "by myself" that is alone he takes distances from that room.
In opposition to the applause he enjoys "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 its stars.
His, is a very different approach from the learn'd astronomer.