Barzillai, the youngest son of Zenas and Roxanna Snow, was born in Lunenburg, Vermont, December 3rd, 1840. His mother died in 1845, when he was just four years old. His father married for a 2nd time, in 1845, Phebe Dustin Spaulding. He remained with his father on the farm until he was twenty-one years of age.

During the Civil War, on the 15th of September 1862, he enlisted as a nine months man in the 15th Vermont Regiment, Company E. His regiment was present at the battle of Gettysburg and helped drive Lee across the river. His term of service expired in August of 1863. In September of the same year, Barzillai went to Boston at the invitation of Mr. Samuel B. Hobart, his brother-in-law, a railroad engineer, and at the urgent request of his sister, Annette (Snow) Hobart. He became a fireman for the Boston and Albany Railroad, soon becoming an engineer on the Grand Junction branch.

While at work, on Friday noon, June 30th, 1871, he had laid down to rest in the engine house at East Boston. His feet projected over the track, and another engine, slowly backing in, ran over both his feet, taking one completely off and breaking several bones in the other, so that it was most probable the other foot would have been amputated. He was taken to Massachusetts General Hospital.

He and his fiancée, Miss Addie Myers, his cousin, were to be married in September. After he was severely injured, they were married on July 2nd, 1871. According to an article in the Lowell Daily Citizen and News (Friday, July 7, 1871, p. 2) "He was married to Miss Addie Myers, a young lady to whom he was engaged, while on his death-bed at the hospital on Sunday afternoon. Miss Myers went to the hospital to nurse Mr. Snow, but as the rules forbid any but immediate relatives attending, she asked to be married to her betrothed in order to be with him." Two days later, on July 4th 1871, he died from his injuries.