What invention did Mark Twain patent in 1873?

The invention Mark Twain patented in 1873 was a self-pasting scrapbook. Its pages contained dried adhesive that could be moistened, allowing users to attach newspaper clippings, pictures, and other keepsakes without separate paste.

Twain was an enthusiastic scrapbooker and disliked the mess and inconvenience of traditional mucilage. His solution used strips or areas of gum on the pages; a damp sponge activated the adhesive. The U.S. Patent Office granted him patent No. 140,245 on June 24, 1873. Twain had begun developing the idea before filing the application.

The scrapbook was more commercially successful than many people expect: more than 25,000 copies were sold and it earned Twain substantial income. He held three patents in total, including an adjustable garment strap and a historical trivia game. The scrapbook is often confused with a fountain pen or typesetting machine, but Twain invested in a failed typesetting venture rather than inventing one.