From the Project Gutenberg version of Exercises in Knitting by Cornelia Mee.
"No. 10 Mee's Persian thread, and needles No. 22, are the proper sizes." Not sure what size thread that is, but if 22 is equivalent to wire gauge (22 per inch), that would be 1.15mm. Considering that the cast on is 152 ("Cast on 56 stitches on the first needle, and 48 on each of the other 2."), …
From the Project Gutenberg version of Exercises in Knitting by Cornelia Mee.
"No. 10 Mee's Persian thread, and needles No. 22, are the proper sizes." Not sure what size thread that is, but if 22 is equivalent to wire gauge (22 per inch), that would be 1.15mm. Considering that the cast on is 152 ("Cast on 56 stitches on the first needle, and 48 on each of the other 2."), and that it goes up to 212 stitches within the first 20 rounds, the yarn and needles must be fairly thin.
Rows 19-22 should be repeated 45 times.
Shown with a cast-on count of 152 stitches.