The reasons why one English merchant, Robert Balle, should have wished to join The Royal Society in 1708 and become thereafter an active member of it are discussed in this paper. The author has used the Journal and Minute Books of The Royal Society, the correspondence of Sir Hans Sloane and other contemporary materials, published and unpublished. She concludes that the factors involved in Balle's decision included family connections, genuine interest in some of the subjects with which the Society was concerned and a belief in the need for the free exchange of ideas. They co–existed with Balle's wish to utilize membership of the Society to further his social and commercial ends and his use of scientific patronage for the enhancement of self–esteem and personal prestige. It is hoped that this study will contribute to the discussion on merchant membership of, and activity within, the early Royal Society.