The Handbook of Wool Knitting and Crochet, published by Needlecraft Publishing Company, Augusta, Maine, 1918 states:

“The women of America are knitting as never before. In the social set, no gathering can be fashionable that does not tolerate knitting; the business woman must needs knit on the car to and from her work; while to the busy housewife no duty is so imperative as to exclude knitting from the daily routine. It almost seems as if the women of America—all women, rich and poor alike—were devoting their united efforts to one vast universal consecration—the comfort of our boys over there.”

The book also contains knitting patterns in the section called,

Knitting for the Red Cross

Using official Red Cross photographs to illustrate, KnitYourBit.com  presents these knitting patterns for you!

1. A Lesson in Knitting (This is a good reference for the patterns below - gives explanation of the terms and stitches used)
2. Sleeveless Sweater
3. Washcloth
4. Service Sock
5. One-Piece Helmet
6. Muffler
7. Hot water bottle cover
8. Helmet made in two parts
9. Thumbless Mitt or Wristlet
10. Bed Sock

Yarn used for the above patterns was Knitting-Worsted - in Regulation Blue, Gray and Khaki .

Special Note: See other, not Red Cross, Vintage Knitting and Crochet Patterns  from The Handbook of Wool Knitting and Crochet