This section is from the book "School Needlework. A Course of Study in Sewing designed for use in Schools", by Olive C. Hapgood. Also available from Amazon: School Needlework: A Course Of Study In Sewing Designed For Use In Schools.
An edging is a trimming on the border of a garment.
Lace edging is made of fine threads woven into a net.
No. 9 needle, No. 70 thread, pins, half-a-yard of inch-wide lace, and a piece of cotton cloth six inches long and four inches wide, with a narrow hem at the ends and upper edge, and an inch hem at the lower edge.