The backing track for Eleanor Rigby was recorded with a string octet the day before. On this day, Paul McCartney added his lead vocals onto track four, and he, John Lennon and George Harrison sang harmonies for the chorus on track three.
The song was considered finished at this stage, and three mono mixes were made during this session. However, George Martin requested an additional vocal overdub from McCartney on 6 June 1966, leaving these mixes redundant.
The Beatles had recorded the backing track for I'm Only Sleeping on 27 April. On this day, however, they recorded five takes of a remake.
Only the first of the five performances was complete, and featured acoustic guitars, percussion, and vocals by Lennon and McCartney, all of which were recorded simultaneously onto track one of the four-track tape. It was eventually released on 1996's Anthology 2.
The Beatles evidently thought this version inferior to the 27 April one, and they returned to take 11 from that night to overdub further instruments. Lennon added his lead vocals, with the tape running at 45 cycles per second instead of the normal 50. Upon playback, therefore, it sounded faster and higher.