{{explanation}}
2 chords - 2nd chord 3s & 4s cross to opp sides

1-8
: 1s+2s & 3s+4s dance 1/2 R&L; all set, all cross RH
9-12
: 2s+1s & 4s+3s dance RH across
13-16
: 1M followed by 1L casts up round 2M, 1M dances down centre to face 3L &
  1L faces 2M **while**

: 4M followed by 4L casts down round 3M, 4M dances up centre (passes 1M
  LSh) to face 2L & 4L faces 3M

: Positions now: lines of 4 across, 1L & 4M at top between 2s facing down,
  1M & 4L at bottom between 3s facing up
17-24
: Reels of 4 across. Bar 24: centre dancers instead of passing LSh 1/2
  turn LH (Men polite turn). Lines across 2L 4M 1L 2M face down, 3L 4L
  1M 3M face up
25-32
: 1s+4s set, Petronella turn in tandem (Ladies lead); 1s+4s turn partners
  RH. End 2 4 (1) (3)