Mercer's religious observances were irregular, although usually when he
was home he attended Potomac Church. At the same time he continued as a
vestryman in Overwharton Parish (which included Potomac and Aquia
churches). On September 28, 1745, the vestry met to decide whether to
build a new Aquia church or to repair the old one. They "then proceeded
to agree with one _William Walker_, an Undertaker to build a new brick
Church, Sixty Feet Square in the Clear, for One Hundred and Fifty Three
Thousand Nine Hundred and Twenty Pounds of Transfer Tobacco."[115] In
October Mercer entered in Ledger G, under the Overwharton Parish
account, "To drawing articles with Walker." In December he charged the
parish with "2 bottles claret" and "To Robert Jackson for mending the
Church Plate." Jackson was a Fredericksburg silversmith.[116]
The following March, the proprietors of the Accokeek Ironworks
petitioned the Committee on Propositions and Grievances with an
objection to the vestry's decision to rebuild, claiming that "as the
said Iron-Works lie in the Parish aforesaid, and employ many Tithables
in carrying on the same, they will labour under great Hardships
thereby...."[117] The petition was rejected, but nothing seems to have
been done on the new church until three months after Walker's death in
February 1750, when Mourning Richards was appointed undertaker.[118]
Mercer's charities in this decade form a short list. His only outright
gift was his "Subscription to Protestant working-Schools in Ireland. To
my annual Subscription for Sterling £5.5." In 1749 he did £12 3s. worth
of legal work for the College of William and Mary, which he converted
into "Subscriptions to Schools" of equal value; in other words, he
donated his services.