enthusiasm. They often made excursions together on foot through the country lying within thirty miles around Boston for the purpose of examining its geological structure and collecting mineralogical specimens. The result of these researches was a volume on the Mineralogy and Geology of Boston and its Vicinity, published by the brothers about the time they completed their medical studies.
The younger brother also employed himself upon these excursions in searching for entomological specimens, and formed quite a large collection of beautifully prepared insects. This was afterward given to the Linnæan Society of New England, of which the brothers, if not the founders, were among the earliest members. Another taste which formed a strong bond of union between them was their love of music. In college they belonged to the same musical societies.
On graduating from college Samuel began reading law with his uncle, Judge Samuel Dana, then residing in Charlestown, Mass. The War of 1812 was in progress, and young Dana caught the prevailing military spirit. He applied for a cadetship at West Point, but received instead a commission as first lieutenant in the First United States Artillery, with which corps he served in New York and Virginia until the close of the war. In June, 1815, the army was disbanded and Dana resigned his commission.
A younger brother, Nathaniel G. Dana, was a cadet at West Point during the War of 1812, graduating in 1814. He remained in military life until his death in 1833.
Samuel did not return to the law, but took up the study of medicine under Dr. Bancroft, of Groton. Receiving his medical degree in 1818, he began the practice of his profession in Gloucester, Mass. The next year he married Ann Theodora, daughter of Eev. Joseph Willard, D. D., who had been President of Harvard College from 1781 till his death in 1804.
Dr. Dana now took up his abode in Walthara, Mass., where he practiced medicine until 1826. Toward the close of this period he established a laboratory for the production of sulphuric acid and bleaching salts. This enterprise soon developed into the Newton Chemical Company, of which he was chemist till 1834. His friend Dr. A. A. Hayes, in the memorial pamphlet of the Dana family, has testified to his wide knowledge of the properties of substances and his great fertility in original devices for general and technological work. In his manufacture of acids and other chemicals improved plans and processes were early employed, and Dr. Hayes mentions especially Dana's device for deoxidizing manganic oxide by heating it with sulphur in order to form from it (with pyroligneous acid) a crude manganous acetate, then largely used in dyeing a fast brown.