Society of Antiquaries ... At the meetings of the Society, held every Thursday evening, from the third Thursday in November to the third  Thursday in June, commencing at 8. Strangers are allowed to attend by permission of the president of the fellows present.

The Society of Antiquaries, which holds its meetings on the same floor as the Royal Society, and on the same evenings, was originally founded in the year 1572, by the learned Archbishop Parker, Sir Robert Cotton, Camden, Stowe and others. It is governed by a president, and council of twenty-one fellows, the members being unlimited, and elected by ballot. Various interesting volumes and prints, in illustration of English antiquities, have been published by this society, independently of eighteen volumes of the "Archaeologia," which is a collection of the most interesting papers read at the meetings. Many curious antiquities of different descriptions, and rare works, are possessed by this Society.

Mogg's New Picture of London and Visitor's Guide to it Sights, 1844

The SOCIETY OF ANTIQUARIANS OF LONDON, Somerset House, was formed into a society in 1717, obtained a charter in 1751, and took possession of their present apartments in 1781. Members are elected by ballot, on the nomination of at least three members (F.S.A.).; entrance fee, 5l. 5s.; annual subscription, 2l. 2s.; life membership, 26l. 5s. They publish, periodically, Transactions, entitled the "Archaeologia," commenced in 1770, which embodies a great variety of antiquarian knowledge.
    In the Library (between 7000 and 8000 volumes) and the Museum some few interesting relics of past ages are preserved, and some maps, plans, and pictures of value from their quaint antiquity. Amongst these may be enumerated a fine collection of proclamations and broadsides; the "Household Book" of the Duke of Norfolk; a brass gilt spur, in scribed with the legend, "en loial amovr tout mon coer," found on Towton battle-field; a Bohemian astronomical clock, made by Jacob Zech, in 1525, for Sigismund king of Poland; portraits of various antiquaries, of William Paulet, Marquis of Winchester (d. 1571), Mary I, date 1544, Edward IV., and Richard III.; and a volume containing a curious collection of maps of London. C. Knight Watson, Esq., M.A., is the secretary.

Cruchley's London in 1865 : A Handbook for Strangers, 1865