Pain expands the Time — Pianist

Pain-expands the Time-1
Ages coil within
The minute Circumference
Of a single Brain-

Pain contracts-the Time-5
Occupied with Shot
Gamuts of Eternities
Are as they were not-
(F.833/J.967)
[1] Pain:: labor of practising piano. expands the Time:: time seems longer in painful practising.
[2] Ages coil within:: to repeat for many years.
[3] minute Circumference:: not given out any detail.
[4] Brain:: brain work of a composer.
[5] contracts:: combines firmly.
[6] Time:: the ryhthm.
[7] Shot:: hit on the piano key. Gamuts:: the compass or full range of notes which a voice or instrument is capable of producing (OED 3b). Eternities:: eternal works of music.
[8] they were not:: a pianist performs as if the gamuts are not there, without limit of notes.