Final answer:
In 'Il Penseroso,' to 'sit and rightly spell' means to contemplate and understand the cosmos and nature.
Step-by-step explanation:
In the poem 'Il Penseroso' by John Milton, when the speaker says he "may sit and rightly spell," he is expressing a desire to study and comprehend the cosmos and nature in a contemplative, meditative state. This act of "spell" is akin to interpreting or understanding the deeper meanings of the universe.
The poem celebrates contemplation and the pursuit of wisdom through reflection and study of the stars and natural world. The speaker's use of 'rightly spell' implies an accurate and true understanding of the mysteries of the heavens and earth, potentially reaching a level of knowledge comparable to prophetic insight.