One of my readers emailed me to ask about a stitch called double stem stitch. And I checked all my embroidery books and didn't come up with anything. But many stitches are called by different names depending on where they originated and are used, so I think I may have found it but named alternate stem stitch. Feel free to correct me if I'm wrong.
So, as a quick refresher, stem and outline stitches are done the same way except that stem stitch holds the thread below the needle (diagrams 1 and 2) and outline above (3). Alternate stem stitch is going to use both of these methods combined.
Work along a line as for stem stitch but, instead of holding the thread below the needle for every stitch, hold it alternately below for the first stitch (ABC), above for the second (CDB), below for the third (EGF) and so on. See the first diagram (4).
The second diagram (5) shows what happens when you work two rows closely together. Start the second row at "a", holding the thread above for the first stitch, below for the second, etc.
Diagrams from Stitches with Variations: A Handbook of Basic Stitches by Jacqueline Enthoven. ©1976 Sunset Designs. Many thanks to Patricia in NJ (my 'personal shopper') for sending me the book!