Liz Clark suggests in her document on dressing girls that a girl's chemise can be basically like a woman's. She suggests the length be about to the knee, but this one is rather short.
The woman's shift (chemise) in The Workwoman's Guide looks like this (Plate 6, corresponding with pages 46-49):
The child's shift (chemise) looks like this:
I'm not sure what the deal is with that flappy thing hanging down in front, so I went with a rounded neck (which the Workwoman says is an option, too, at least for a woman's chemise, don't know about a kid's).
- Top of the trapezoid: 18"
- Bottom of the trapezoid: 25"
- Height 21"
- Arm depth: 6.25" (however, I had to make it deeper because of the gusset in the sleeve)
- Shoulder seam (distance from edge to short line in Fig. 10): 3.5"
- Lowest point of rounded neck, center front: 4.5" (I wouldn't make it this deep in the future)
I used 45" wide muslin. I tore a 21" strip across the entire width. Then I tore my main body down to 25" wide. I folded my main body in half, measured out 9" from the center top and marked a slanted line down to the bottom corner and cut (see picture).
Then I took the cut off pieces and stitched them to the sides of the remnant I discarded earlier. It makes a perfect back. (Although, I could have steepened my slope, which would have given me a little more fabric to work with at the pointy end).
I cut out my neck, then stitched my side seams and shoulder seams. I should have definitely made the back neck opening not as deep as the front -- and made the whole thing more shallow.
For the sleeves I used 2 strips: 12.5" x 4". The little triangular gussets are just a 4" square cut diagonally, then sewn to the short ends of the long rectangles.
I hemmed sleeves before setting them into the chemise. You can hem the bottom of the chemise any time.
A modern construction where you sew the sleeves to the body before sewing the side seams would have worked really well with this shape.
Because the neck was so huge, I put some pleats in both center front and back, so it is just big enough to fit over my daughter's head. For some reason the neck gets weighed down funny in front. Good thing it's going UNDER her dress! So, not my best work, but hey, look what I'm working with!
View of the gusset: