{{explanation}}
 3s & 4s start on opp. sides

1-8
: 1s+2s also 3s+4s dance 1/2 double Fig of 8 (2s & 3s cross up/down to
  start), 1M+2M also 3M+4M turn RH on sides **while** partners turn LH
9-16
: Repeat using other hand to turn on sides
17-24
: 17-18 2L+3M cross to Men's side (2L passing in front of 3M to 3rd place,
  3M to 2nd place) **while** partners cross to Ladies' side opp partners

: **19-20** 2M+3L cross back to Men's side (3L passing in front of 2M, 3L
  to 2nd place, 2M to 3rd place) **while** partners cross to Ladies'
  side opp partners

: **21-24** 3s (in 2nd place) turn partner RH **while** 2s turn LH
25-32
: 2s & 3s repeat 17-20 back to original place; 2s turn RH **while** 3s
  turn LH
33-40
: All Petronella turn into centre, set & 3/4 turn RH, 1s+2s also 3s+4s
  dance 1/2 RH across. 2 1 (4) (3)
41-48
: 1s+4s dance LH across, 2s+1s also 4s+3s dance RH across
49-56
: All dance reels of 4 on sides ending 1M & 4L also 1L & 4M passing RSh
  giving RH into prom hold to face each other across set
57-64
: 1M+4L & 4M+1L promenade 1/2 way round each other (Ladies passing RSh. On
  4th bar they dance in to join nearer hands with partner with 4s in 2nd
  place facing up & 1s in 3rd place facing down; 4s & 1s dance up/down &
  cast to 2nd/3rd place. 2 4 (1) (3)