~when you are old~
1.When you are old and grey and full of sleep
---grey:lustreless,dull
---full of sleep: weariness;peace;proximity to death
2.And slowly read, and dream of the soft look. Youe eyes had once,and of their shadows deep.
---slow,soft,shadow:a sense of stupor
---shadows deep:a sense of the unknown and the mysterious,perhaps implying the calm retained by a person who has not experienced the bitter aspects of life or the ravages of time=innocence
3.pilgrim soul:journeying soul--searching for a place of devotion, moving through life towards the final significance of death and salvation.
4.and paced upon the moutains overhead, and hid his face amid a crowd of stars:suggests Yeat's romantic heartbreak, disturbed and fuddled, yet attaining the magnitude of the universe in the his feelings.