Nancy Maria Donaldson Johnson was born on December 28, 1794, in New York, USA.

She was a missionary and inventor. Nancy, along with her sister Mary, was very active as a missionary for the American Mission Society. In 1862, they both participated as missionaries and teachers in the 'Port Royal Experiment' to teach freed slaves in South Carolina. As an inventor, she was awarded the first US patent for a hand-cranked ice cream freezer in 1843. She created a system that allowed the ingredients to be agitated without human intervention. Her simple invention launched a “disruptive technology” that made it possible for everyone to make quality ice cream without electricity. She received $1500 during the course of her life for her patent but in 1848, she sold the rights of the patent to William G. Young, a Baltimore businessman, who then improved on the ice cream freezer. Over 150 years later, and Johnson’s invention is still used today, e.g., a very similar model is still widely used in Guadeloupe and Martinique, which is often referred to as "West Indian Ice Cream Maker".

In 1824, she married Prof. Walter Rogers Johnson (1794–1852), a scientist and the first Secretary for the American Association for the Advancement of Science. She died on April 22, 1890, in Washington, D.C.

Prof. Walter Rogers Johnson was born on June 12, 1794, in Leominster, Worcester, Massachusetts.

He was an educator, educational reformer, scientist, and author. He graduated from Harvard College in 1819 and started to teach first at Framingham Academy and later at Salem Academy, Mass. He served as principal of the Germantown Academy, Penn. In 1826, he moved to Philadelphia and taught at Franklin Institute. In 1839, he became Professor of Chemistry and Natural Philosophy at Pennsylvania College at Gettysburg. He was deeply interested in the cause of public education. He became the first Secretary of the American Association for the Advancement of Science in 1848. He also did research on coal for the Smithsonian Institution in Washington, D. C., and published numerous books related to his research.

In 1824, he married Nancy Maria Donaldson (1794–1890), a missionary and inventor of a hand-cranked ice cream freezer. He died on April 26, 1852, in Washington, D.C.

William Arthur Johnson was born in Bombay. The Duke of Wellington was his godfather. Although intended for the army, Johnson, after migrating to Upper Canada in 1831, entered the Anglican Church. He was a curate to Archdeacon A.N. Bethune at Cobourg. However, his tractarian tendencies made him unpopular and he was made rector of St.Philip's at Etobicoke, a remote village across the river from Weston. There he established a school that was to become Trinity College School. Among Johnson's pupils was William Osler, who regarded Johnson as one of his mentors.

William James Johnson was born on August 18, 1833, in Inverness, Quebec. A prominent merchant, He was Consulting Mining Engineer for the Canada Life Building, as well as Director in Johnson's Asbestos Company.

In 1869, he married Emily Ward. He died on April 30, 1910, in Lachine, Quebec.