a score of similar indexes to special topics have been produced. In 1876 he published an Index to the Literature of Manganese.
At the Montreal meeting of the American Association for the Advancement of Science (1882) he chose for his vice-presidential address the subject Chemical Literature, and suggested the formation of a committee on indexing chemical literature; as the chairman of this committee he has prepared ten annual reports to the association, and has done much to encourage the production of special chemical bibliographies by American chemists.
One of the most important bibliographical works by Dr. Bolton is his Catalogue of Scientific and Technical Periodicals, 1865-1882, published as vol. xxix of the Smithsonian Miscellaneous Collections in 1885. This comprises full titles of over five thousand scientific technical journals in about twenty languages, together with chronological tables showing the year of issue of each volume of five hundred periodicals, and a library check-list indicating in what American libraries sets of these journals are to be found. This undertaking was a labor of love on the part of Dr. Bolton, who, in the words of an eminent writer, acquired thereby "a place in the foremost rank of those little-appreciated and hard-worked men, bibliographers." Dr. Bolton has just completed a still more extensive work of a kindred nature, A Select Bibliography of Chemistry, 1492-1892. This general bibliography of chemical science comprises over twelve thousand titles in twenty-four languages, yet is a "select" catalogue, and makes no claim to completeness. The titles are arranged under seven groups, as follows: I, Bibliography; II, Dictionaries; III, History; IV, Biography; V, Chemistry, pure and applied; VI, Alchemy; VII, Periodicals. The volume contains 1212 pages, and forms No. xxxvi in the series of Smithsonian Miscellaneous Collections.
Parallel with his original researches and bibliographical compilations Dr. Bolton has given much attention to the history of chemistry, contributing many notes to current scientific journals, of which the following is a partial list:
Contributions to the History of Chemistry.—Historical Notes on the Defunct Elements, American Chemist, 1873. Views of the Founders of the Atomic Philosophy, American Chemist, 1873. Notes on the Early Literature of Chemistry, several papers in American Chemist, 1873-'79. Papyrus Ebers, the earliest medical work extant. Quarterly Journal of Science, London, 1876. Ancient Methods of Filtration, The Popular Science Monthly, 1879. Early Practice of Medicine by Women, The Popular Science Monthly, 1880. History of Chemical Notation (two papers). Transactions of the New York Academy of Sciences, 1883. Recent Progress in Chemistry, Transactions of the New York Academy of Sciences, 1886. The Lunar Society of Birmingham, Transactions of the