[3] His sister, Margaret Olivia Slocum, was the wife of Russell Sage (from whom she inherited his entire $70 million fortune following his 1906 death).
After the Panic of 1837 and the decline of canal traffic following construction of railroads across the state, her father's businesses and warehouses began to fail.
[5] Slocum served "with honor" in the Civil War,[6] and afterward resigned from the Union Army to go into business in Cincinnati.
In 1878, he moved to New York to join Russell Sage, his brother-in-law, in business, serving as Receiver, Treasurer, and director of the Poughkeepsie and Eastern Railway.
Slocum died on October 2, 1924, at 791 Madison Avenue, his home in Manhattan where he lived with his daughter and son-in-law.