American journalist, born in Albany, NY, on the 12th of August 1815; died there on the 23rd of January 1873. He was a graduate of Union College in 1834; studied law and was admitted to the bar, and in 1840–42 was state librarian. In 1843 he became editor of the Albany Atlas, a Democratic daily. In 1856 the Atlas and Argus were consolidated, and he became editor. In 1865 the paper was called the Argus. Mr. Cassidy, from 1868 till 1873, was secretary of the Democratic State Committee, and framed the celebrated antislavery plank which suffered defeat at the convention at Herkimer. In 1872 Governor Hoffman appointed him as one of a committee of sixteen to revise the constitution.