I finished my new chemise and finally got around to also adding the laundry markings. This chemise was drafted from the directions on the Sewing Academy website (also available in the Dressmaker's Guide by Elizabeth Stuart Clark). It's made out of bleached muslin and embroidered on the lower right hem. This is by far the most comfortable of the three chemises I have - the others have fitting issues in the sleeves and around the neckline. I find that these make the most wonderful nighties, and have plans to make atleast one more from Simplicity 2890.
Laundry Markings were used as a way to differentiate one woman's laundry from another when being washed. This was an issue historically as undergarments were all white and the general styles varied very little from each other. They were usually worked in tiny cross stitches in either red or black in an inconspicuous spot. If a lady was part of a gentleman's household then her first initial was preceeded by his first initial and then followed by the first initial of the family name. So my laundry marking is Jonathan Angela Oehlert. Then would follow details of the fabric, such as Bleached Muslin, then perhaps the number of the garment (if you numbered your household linen), and finally the year as shown above. It wasn't difficult to work and I quite the looks of my marked laundry.