A descendant of Joseph Arnold has research papers from an uncle that show his wife's name as Mercy rather than Mary as found in Rhode Island Vital Records. They are said to have had a number of children. Other than Samuel they were Eleazer, Joseph, Benjamin, Amos, Elizabeth, Caleb, Deborah, Joshua, Stukley, and Mercy.
It is likely Eleazer was the son of a first wife, her name unknown. Eleazer enlisted in his Majesty's service and went to Cape Breton, Nova Scotia, where he died 26 Oct 1745. His personal estate was left to his brother Amos Arnold.
Joseph was 38 when he married Mercy "Mary" Stafford at the Narragansett Society of Friends.
Joseph's will was dated 13 May 1746; proved 17 Nov 1746. He did name his wife Mercy, sons Benjamin, Caleb, Joshua, Nathan, Stuckeley, and Samuel, the last four under age 21, Amos, and Joseph; and daughters Deborah and Mercy. A daughter Elizabeth had died in October, 1745, and was not named.
I have listed only the children that had other connections in my database..
Joseph ARNOLD and Mercy "Mary" STAFFORD were married on 20 June 1716.71,72 Mercy "Mary" STAFFORD, daughter of Amos STAFFORD and Mary BURLINGAME, was born on 21 September 1694.73 She died in December 1779 at the age of 85.
The death of Marcy Arnold, widow of Joseph, at Smithfield, aged 86 years, was noted in the Providence Gazette, 18 Dec 1779.
Joseph ARNOLD and Mercy "Mary" STAFFORD had the following children: