The main series of general nineteenth century correspondence has been arranged in volumes under the names of the officers of the societies receiving them. As more than one Society's correspondence is in this section, an attempt has been made to distinguish between the letters received by each. There are four main divisions:

Division 1 (C1-C121)

The first consists of correspondence of secretaries and assistant secretaries of the Committee on Slavery and the British and Foreign Anti-Slavery Society that developed from it, of the treasurers, presidents and chairman, and other committee members of that Society, together with the secretaries of the National Freedmen's Aid Society, who were also most active committee members of the British and Foreign Anti-Slavery Society.

The names and dates of the Societies' officers etc., in the order in which they appear in section C, are as follows:

Committee on Slavery

British and Foreign Anti-Slavery Society (dates taken from the minute books of the Anti-Slavery Society)

Other officers and members of the Anti-Slavery Society and of the Aborigines' Protection Society

Division 2 (C122-C153)

The second division consists of the correspondence of the secretaries and one treasurer of the Aborigines Protection Society until 1909. Since only one minute book of this Society survives it has been impossible to give the exact dates of the officers' appointments. The three secretaries were Thomas Hodgkin, followed by F. W. Chesson until his death in 1888, and H. R. Fox Bourne who died in 1909. The Treasurer was R. N. Fowler, at one time Lord Mayor of London.

Division 3 (C154-C160)

The third division is formed by letters written to people holding no major office in any of the societies, those letters where the recipient is untraceable either by mode of address or by endorsements, and by anonymous fragments of letters.

The first volume has four groups of letters forming the correspondence of Joseph Booth (1919), James Long (1857-1894), Richard Allen (1840-1873) and J. H. Hinton (1830-1870). The next six volumes of entirely miscellaneous letters are arranged in alphabetical order.

Division 4 (C161-C166)

The fourth division is of official letters from prime ministers, government offices, foreign legations etc. to officers of the several societies. Within the groups of letters sent to each officer of a Society the arrangement is according to seniority of the office sending the letter i.e. prime ministers, Home Office, Foreign Office, Colonial Office and War Office, and the India Office. The letters are then, of course, arranged chronologically.

In addition to the list of these volumes, a card index of the letters is available. The cards are arranged according to the names of the writers. Each card bears also the names of the place or places from which the letters were written, the name of the person to whom they were written, usually an officer of one of the societies, but if they were written to someone else and then came into the hands of an officer of a Society, both these names are given, the outside dates of the letters are given, the number of letters, the shelfmark of the whole section, MSS. Brit. Emp. s. 18, the number of the volume e.g. C1, and the serial number of the letters e.g. 85-93. This index is cross referenced under the names of persons other than officers of the societies to whom the letters were sent and also under place names. Thus it will be possible to trace the letters in this section from or to any particular person by consulting this index or, in the case of officers of the societies, the list for section C below. Readers interested in a particular place, e.g. Jamaica or Birmingham, should be able to trace letters from these places from the index and from the list of section G described below.