UPDATE: Thank-you to Jacqui and her husband from Treadle Quilts for finding out that this machine is a Model 66 one of 50,000 that was commissioned in December of 1916.
For our summer holiday this year my husband and I spent a few days at my mom's house. She is getting on in years and my sisters and I are trying to clear out some of her "treasures" that she has accumulated over the years. While clearing out one of the bedrooms we came across this sewing machine. Since I am the one who does the most sewing-neither of my sisters are quilters-this beauty came home with me. The problem is I have no idea of its age or history. Does anyone in blog land know how I can find out the age of this machine? Any help would be appreciated.