Henry was born in
Southampton County, Virginia, to
Captain Peter and Elizabeth (Taylor) Blow, owners of the famous enslaved man
Dred Scott. Blow was the eighth of ten children. He moved with his parents to
Huntsville, Alabama, where his father unsuccessfully tried farming. and started apprenticing in a law office, but was forced by the deaths of his parents to become a clerk in his brother-in-law Charless' business, selling paint and oil. Peter Blow had left his estate to his two unmarried daughters and Henry's younger brothers, Taylor and William. Henry was only fifteen when his father died, but that was old enough to be seen as a man able to survive on his own. Henry's married sister, Charlotte Taylor Blow, also did not receive an inheritance. She married Joseph Charless Jr. in 1831. Charless' father
Joseph had founded the first newspaper west of the Mississippi. The Charless family helped Henry after the death of his father and Henry began working as a clerk at their wholesale drug and paint company. When Joseph Charles Sr. retired in 1836, Henry was made a partner in the business. In 1838, the business was renamed Charless, Blow, and Company. Only a few years later, in 1844, the partnership was dissolved. Charless retained ownership of the drugstore and Blow kept the manufacturing firm, which was later known as Collier White Lead and Oil Company. The Collier Company was one of the largest factories in St. Louis. Charless, Blow, and Company was not the only business that Blow would lead. Henry and his brother, Peter, created the Granby Mining and Smelting Company. Henry also served as president of the Iron Mountain Railroad for a time and helped to establish a furnace for the iron industry in Carondelet. ==Political life==