Jottings on the Nile and in the Desert, Bulletin of the American Geographical Society, 1890. Historical Notes on the Gold-Cure, Popular Science Monthly, 1892. A Plea for a Library of Science in New York City, 1893. Russian Transliteration, American Library Journal, 1893.
In 1880 Dr. Bolton became interested in folk-lore, and published two years later a work bearing the title, Counting-out Rhymes of Children (London, 1888), which brought him at once into prominence as a folk-lorist. Since then he has contributed occasional papers to the Journal of American Folk Lore, of which the most notable are the two following: Some Hawaiian Pastimes (1891) and A Modern Oracle and its Prototypes (1893). His work on Counting-out Rhymes was awarded a bronze medal by the Columbian Historical Exposition held at Madrid' in 1892.
After the death of his mother in 1887, Dr. Bolton resigned from Trinity College, retired from teaching, and resumed his residence in New York city. He has been able to indulge his love of travel by frequent journeys abroad; besides the five years' sojourn in Europe already named, he visited in 1873 the principal libraries of England, France, and Germany, to collect material for his Bibliography of Scientific Periodicals, the publication of which was, however, from various causes delayed until 1885. In 1880 he visited Norway, Sweden, and Denmark; in 1887 and 1888 he made a second and a third bibliographical tour in Europe; in 1889 he visited Egypt, going as far as Mount Sinai; in 1890 he visited the Bermudas and the Hawaiian Islands. These distant points were visited in search of "musical sand." In 1891 he again crossed the Atlantic, chiefly for research in libraries. Dr. Bolton has been heard to say he never travels to kill time or to satisfy mere curiosity; he always has some definite object in view and works harder on his journeys than otherwise.
Dr. Bolton is often called upon to give illustrated lectures on his travels and on popular science. Being an amateur photographer he brought back with him from Arabia Petræa and from the Hawaiian Islands many excellent negatives with which he illustrates his lectures. These include the following subjects: Four Weeks in the Desert of Sinai, Life and Scenes in the Hawaiian Islands, Picturesque Scenes in Norway, Alchemy the Cradle of Chemistry, The Counting-out Rhymes of Children, The Glaciers of Switzerland, Musical Sand, etc.
In 1892 he was elected by the Trustees of Columbian University Non-resident Professor of the History of Chemistry, and in the discharge of his duties gave in March, 1893, a course of nine lectures on the history of chemistry. He treats this subject in a graphic way, making it attractive to the general audience by illustrating every step with the lantern.