Brass and Wood 5 Line Chalk Drawing Tool (for Penmanship and Music) with Blue Chalk

Another beautiful tool, and, this one, to my mind, with all sorts of possibilities for creative mark-making applications now, for me there is something about blue chalk that just inspires a sense of creativity. This would once have been used for drawing a staff of five lines on a school chalkboard--either for music class, or to provide guides for writing on the board/penmanship practice. The wooden dowel rolls smoothly, and would press against the board as the chalk did its work drawing the lines. I've seen some cruder versions of these out there, but this old brass one with turned wooden handle and hanging hook at the end is as lovely as any I have seen.

10 1/4" w x 8 5/8 l and in very good condition, early 20th c. I believe.