The following data is extracted from Stone Family History.
EDMUND: (d. 1768); mathematician; son of the gardener of the second Duke of Argyle. The Duke, once seeing a copy of Newton's "Principia" lying on the grass, supposed it to be his own and had it carried to the library. Young Stone claimed it, however, and a conversation ensued in which the Duke learned, to his surprise, that without teachers the young man had acquired a considerable knowledge of mathematics and had mastered the rudiments of Latin and French. The Duke placed him where he could pursue his studies. He was author of many works, the first being "The Construction and Principal Uses of Mathematical Instruments." The death of the Duke of Argyle seems to have affected him greatly, for he withdrew from the Royal Society and spent the remainder of his life in poverty.
Source: Stone Family History