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

1-4
: 1s+2s also 3s+4s dance 1/2 Double Fig 8 (1s/4s cross down/up, 2s/3s
  dance up/down)
5-8
: 1s & 4s turn partner 1.1/2 RH **while** 2s+3s change places on side
  turning 1.1/2 LH
9-12
: 1s+3s also 2s+4s dance 1/2 Double Fig 8(1s/4s cross down/up, 2s/3s dance
  up/down)
13-16
: 1s & 4s turn partner 1.1/2 RH **while** 3s+2s change places on side
  turning 1.1/2 LH
17-24
: All dance Grand Chain, 1s & 4s cross, 2s+3s change places on side to
  start. Omit polite turns
25-28
: All 1/2 turn partner RH flowing into 2s+1s also 4s+3s dance 1/2 RH
  across;
29-32
: 2s+1s also 4s+3s dance 1/2 LH across, all chase 2 places round
  anticlockwise
33-40
: 1s+4s set, petronella in tandem; 1s+4s Set+Link across to end 2 4 (1)
  (3)