His entrepreneurial spirit led him to also open an ice cream and confectionery store in Philadelphia as a source of extra income.

[1] Around 1854, Newton bought 1000 acres of farmland in Virginia, which he hired overseers to run when his wife refused to live there.

[1] At some earlier point, he had begun selling farm products to the White House, and he had recently made the acquaintance of President Abraham Lincoln, so he was well-positioned to seek a job at a time when the war had filled Washington with place-seekers.

The appointment was controversial; at least one agricultural publication wrote a sarcastic and almost certainly unfair editorial headlined "Who is Isaac Newton?"

[1] Washington journalist Benjamin Perley Poore said Newton was "an ignorant, credulous old gentleman," the butt of jokes, who was all too easily tricked by dishonest contractors.