This ad was placed in Popular Science in 1926 by the Sherwin Cody School of English in Rochester, NY. The rest of the ad was an offer for his home-study course in English. From Wikipedia: The Sherwin Cody 100% Self-correcting Course in English Language arrived in 25 weekly booklets, each divided into five sections. Composition was on Mondays, spelling on Tuesdays, punctuation on Wednesdays, grammar on Thursdays, and conversation and literature on Fridays. The daily lessons were tied to other reference books published by Cody including his Nutshell Library, a collection of pocket books excerpting the works of great writers, supplemented the literary studies. You can read his The Art of Writing and Speaking the English Language here. You can buy the course itself here.