{{explanation}}
1s & 3s start on opp sides

1-8
: 2s+3s dance RH across, 1s+2s also 3s+4s dance LH across
9-16
: All petronella turn into middle, set, 3/4 turn RH to change sides & set.
  1 (2)3(4)
17-24
: 1s+2s also 3s+4s dance 1/2 R&L, end couples 1/2 turn 2H & centre couples
  1/2 turn 2H on sides to end in a square set
25-32
: All dance 1/2 double Men's Chain, couples in 1st & 3rd places set & turn
  2H 1.1/2 times to face Mans corner with Lady behind Man **while**
  couples in 2nd & 4th places continue with another 1/2 Men's Chain
33-40
: Couples in 1st & 3rd places dance Tandem LSh reels of 3 across & end
  curving round to face side couple (1s face 4s & Lady faces Man)
41-48
: All circle 4H round to left, set, side cpls make arch & cpls from 1st &
  3rd pl dance under arches, divide & cast back to form longwise set.
  (2) 4 (1) 3