Molecule models were available preassembled by various manufacturers or suppliers of school and laboratory equipment based in the United States, England, and Continental Europe. They were also offered unassembled as kits for students. Among the preassembled examples that we frequently offer are those by the British manufacturer Crystal Structures, Ltd, mid 20th Century, often with their label printed “CSL, Bottisham, Cambridge, England” and those by E. Leybold’s Nachfolger, Cologne, generally mid to early 20th Century, and sometimes bearing their label. These molecules are sometimes also identified with a printed or hand-written name on the manufacturer’s label or another label.
The broad incorporation of visual aids such as illustrations and three-dimensional models and devices into classroom teaching, now accepted as commonplace, originated in the mid 19th century. In that period, influential educators advocated their use at all levels of education as a more efficient teaching method than lectures alone. Such devices were particularly popular in the United States and Western Europe. The rationale is succinctly encapsulated by Horace Mann in his Lectures on Education, published in 1845 when he was serving as Secretary of the Massachusetts Board of Education:
“The mind often acquires, by a glance of the eye, what volumes of books and months of study could not reveal so livingly through the ear. Everything that comes through the eye, too, has a vividness, a clear outline, a just collocation of parts, — each in its proper place, which the other senses can never communicate. Ideas or impressions acquired through vision are long-lived.”
Mann, Horace. Lectures on Education. Boston: William B. Fowle and N. Capen, 1845. p. 29. Online at Google Books: http://books.google.com/books?id=WfMSAAAAIAAJ (14 June 2011).