This section is from the "Hand Sewing Lessons" book, by Sarah Ewell Krolik. Also available from Amazon: Hand Sewing Lessons: A Graded Course For Schools And For The Home.
Cotton, 5 inches square.
Cotton, 41/2 x1 inch, for band of second placket. Third the square and cut a 2 inch slash down each fold. (See Illustration 13.)
Illustration 13. Square folded into thirds for cutting.