Instructions from 1950’s Semco Crochet booklet
LATTICE STITCH (lat st): Work a chain, then make one knot stitch,
allow three chains for the first treble, and three for the skipped stitches, work a tr in next ch,
* the knot stitch, sk 3 ch, 1 tr.
Repeat for length desired.
This row is repeated for the pattern, working the tr in tr, each time, bringing the knot stitches over each other.