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.
A small twist made from flax, silk, cotton, or wool, is called thread. Thread made from flax is called linen thread, and is very strong. Thread made from silk is called silk or twist, and is used when sewing on nice textures. Cotton thread can be obtained in many numbers, and is used when sewing on wash goods; the finer the thread, the higher the number. Thread made from wool is called yarn, worsted, zephyr, etc., and is used for darning, canvas-work, and fancy-work.
A new spool of thread can be unfastened by slipping a pin under the thread, where it is caught in the wood. To unwind the thread, hold the spool in the left hand, with the end of the thread between two fingers. Unwind the thread until it is of the required length. Break it by holding it securely in each hand, and snapping it across the ends of the thumbs. When not using a spool of thread, keep the end of the thread fastened in the wood.
Use a piece of thread the length of the desk, or about as long as the arm. When using very fine thread, take a shorter needleful. If the thread kinks, remove the needle, and beginning at the work, draw the thread tightly between the thumb-nail and the end of the forefinger. To prevent thread from kinking, thread the needle with the end that hangs from the spool. When using double thread, as in gathering, sewing on buttons, etc., before making the knot, draw the double thread, beginning at the needle, across the wax.