YOUMANS, Edward Livingston, scientist, born in Coeymans, New York, 3 June, 1821; died in New York city, 18 January, 1887. In childhood his parents removed to Saratoga county, where his youth was passed. He attended the common school, and was an insatiable reader, but at thirteen years of age was attacked with ophthalmia. In 1840 he went to New York for treatment, and the city became his home His blindness lasted several years, but he finally recovered partially During these years of suffering and deprivation he was a constant worker and an assiduous student of books and events. He studied elementary chemistry and physics with the aid of his sister, and when he was left to himself his leisure was spent in writing with a pocket-machine of his own contrivance. In 1851, while studying agricultural chemistry, he prepared a, chemical chart that made clear by means of colored diagrams the laws of chemical science as they were then expounded (revised and enlarged, 1856). He studied medicine during this period and received the degree of M. D. from the University of Vermont. In 1852 he began to lecture upon science, and for the next seventeen years he gave courses of lectures in connection with the lyceum system in many towns and cities, awakening deep interest in scientific subjects. In his lectures on the "Chemistry of the Sunbeam" and the "Dynamics of Life" he was the first to expound popularly the doctrines of the conservation of energy and the mutual relation of forces. He early became deeply interested in the diffusion in this country of standard scientific works, and particularly those bearing upon the evolution philosophy, procuring their republication here, and doing all he could through the newspaper and periodical press to make them known to the public. Herbert Spencer's books alone, in behalf of which he spared no effort, have reached a sale of 132,000 copies, and the foreign authors, whose works were in his charge, have for years enjoyed, by voluntary arrangement with the Messrs. Appleton, the benefits of international copyright, of the justice and need of which Mr. Youmans was from the beginning of his literary life an ardent advocate. The " International Scientific Series" was planned by him in 1871, and arrangements were made for the publication of the works in New York, London, Paris, and Leipsic, and afterward in St. Petersburg and Milan. The project was based on the idea of payment to authors from the sale in all countries. The series has reached (1888) its sixty-fourth volume. In 1872 he established the "Popular Science Monthly," and thenceforward the editorial duties of the magazine absorbed his chief attention. The twenty-eight volumes issued under his care show the same devotion to the spread of scientific thought upon the chief topics of the time. His enthusiastic nature led to constant overdoing, and the strain took upon his strength years before his death. From 1882 his lungs were seriously affected, but he worked on persistently until early in 1886. He published " Alcohol and the Constitution of Man" (New York, 1853) ; "The Chemical Atlas," an extension of method of the chemical chart that has been mentioned (1854); "Handbook of Household Science " (1857): "The Correlation and Conservation of Forces," a compilation with an able introduction setting forth America's contribution to the modern doctrine of forces (1864); and "The Culture demanded by Modern Life," a compilation from various authors, presenting the claims of their special sciences as suited for the best culture (1868). His introduction to the volume is perhaps his most finished literary work. He also contributed to the body of the book an original lecture given in London on "The Scientific Study of Human Nature."--His brother, William Jay, editor, born in Saratoga, New York, 14 October, 1838, worked on his father's farm and attended the district-school until his seventeenth year. He studied chemistry under his brother, and in the Yale scientific school, and natural history under Dr. Asa Fitch, was graduated at the medical department of the New York university in 1865, and then went abroad in the same year to continue his studies in natural history under Professor Thomas It. Huxley. He practised medicine three years in Minnesota., but abandoned it to assist in establishing the " Popular Science Monthly," the management of which he shared until the death of his brother, when he became its sole editor. He has contributed occasionally to its pages under his own name, and for many years has prepared the articles on chemistry, metallurgy, and physiology for Appletons' "Annual Cyclopaedia." He is a member of several scientific associations. He has edited Huxley's "Lessons in Elementary Physiology," to which he added a second part on "Elementary Hygiene" (New York, 1867).--Their sister, Eliza Ann, author, born in Saratoga, , New York, 17 December, 1826, became interested in the scientific studies which she aided her brother to pursue, and her fondness for children led her to apply them to early education. She has published "First Book of Botany, designed to Cultivate the Observing Powers of Children" (New York, 1870) and "Second Book of Botany" (1873). These were intended to promote the systematic study of plants as ob-jeers in place of the object lessons in general use. She has prepared an enlarged edition of Henslow's "Botanical Charts" (1873), translated from the French Quatrefage's "Natural History of Man" (1875), and contributed to the "Popular Science Monthly" and other periodicals. Miss Youmans also published "Descriptive Botany, a Guide to the Classification of Plants, with a Popular Flora" (1885), and an abridgment of Bently's "Physiological Botany," as a sequel (1886).