lar Science Monthly, of James Blythe Rogers, the eldest of them, in the June number, and of Robert Empie Rogers, the fourth, in October, 1896.
Henry Darwin Rogers, the third of the brothers, was born in Philadelphia, August 1, 1808, and died near Glasgow, Scotland, May 29, 1866. His middle name was given him in honor of Erasmus Darwin, of whose poem, The Botanic Garden, his father was a great admirer. He was educated at Baltimore and at Williamsburg, Va., where his father was Professor of Natural Philosophy and Mathematics in William and Mary College from 1819 till 1828, the year of his death. The first notice we find of Henry's early work is the mention in Dr. Ruschenberger's sketch of a school set up by him and his brother William in the suburbs of Baltimore. In January, 1830, when he was not yet twenty-two years old, he was elected Professor of Chemistry and Natural Philosophy in Dickinson College. During the year in which he held the professorship he edited a monthly scientific magazine, The Messenger of Useful Knowledge, to which his brother contributed a series of short articles on the Formation of Dew, and in which educational, literary, and political articles and selections from foreign journals were also published. He resigned his professorship at the end of the year, and in 1831 went with Robert Dale Owen to England, where, with aid afforded him by his brother William, he studied chemistry in the laboratory of Dr. Edward Turner, and attended other scientific lectures in London, including those of De la Beche on geology. He returned to Philadelphia in the summer of 1833, and in the ensuing winter delivered a course of lectures on geology in the hall of the Franklin Institute. He was made a member of this society, on the nomination of Alexander Dallas Bache, in January, 1834; was a member of its Board of Managers from 1838 till 1843; and resigned his membership in it in March, 1848.
Having received the degree of Master of Arts from the University of Pennsylvania in 1834, he was elected Professor of Geology and Mineralogy in that institution in 1835. This chair he held—giving regular instruction—till 1846, when he resigned. One of the fruits of his labors there was the small publication, A Guide to a Course of Lectures on Geology, delivered in the University of Pennsylvania.
In 1835 Mr. Rogers was appointed by the Legislature of that State to make a geological and mineralogical survey of New Jersey. He published a small preliminary report of the progress of his work in 1836, and in 1840 a larger report, with maps, entitled Description of the Geology of the State of New Jersey. The report of 1836 gave the first descriptive section that was made of the cretaceous formation of that State, and the first pub-
