In 19th century America the textbook for reading, or "reader," was predominant as the learning tool for young children. Science selections in these readers introduced students to their first formal science instruction. This paper presents an analysis of the science used in 19th century popular readers. Through a synthesis of expert opinion, the most popular readers (n=46) occurring in 20 year intervals were selected, and then analyzed for quantity of science (by page and by article), content of science (biology, earth science, and physical science), and for how science was used. Results indicate that the average percentage of pages devoted to science in the readers during the 19th century was 17.8. The amount of science peaked in the middle of the century. It is suggested that the inclusion of more science in the readers reflected the growing popularity of science in society; however, a push to make reading more literary was in part responsible for the decrease in science observed in readers at the end of that century. The percentage of science selections that were biological in nature steadily increased and the percentage of earth science topics steadily decreased. Science selections in the readers were presented in a variety of formats, including: didactic explanations, dialogues, stories, poetry, and questions with answers. (Contains 26 references.) (PR)