The Gabriel Furman papers consist primarily of several volumes of Furman's Notes and Memoranda, of which the earliest in the collection were also called common place books. These journals span a period from October 28, 1815, when Furman was 15 years old, to September 10, 1854, two months before he died. However, pages are not consistently arranged chronologically, and many entries are undated. Furman was an avid -- perhaps even compulsive -- collector of information on a vast range of topics. Perhaps 75% of his Notes and Memoranda consists of information copied from other sources, rather than his own observations. He noted Dutch colonial laws of New York, ancient proclamations of Parliament, census figures, commerce data, weather reports from around the world, American Indian culture, observations of sea serpents, arguments that the center of the earth could be reached by ship from the North Pole, references to Shakespeare and the arts, and a host of other unrelated topics. These entries range from a line or two to dozens of pages. They are a mix of transcriptions, summaries, bibliographic references, and commentary.

Furman's personal observations include childhood memories of early Brooklyn and street scenes and local color from his walks around Manhattan, Brooklyn and Hoboken. He also noted natural events, such as the appearance of the Aurora Borealis (multiple times) and infestations of black ants and caterpillars. He extensively covers two important historical events: the cholera epidemic of 1832 and the financial panic of 1837. He occasionally comments on contemporary politics, including some reference to the issues of slavery and abolition, but this is not a significant portion of the journals. The highlights of each journal are as follows:

Notes and Memoranda, Vol. 2 (Common Place Book, Vol. 2): circa 1815-circa 1823. Diary while at Columbia Academy (Bergen, New Jersey), 1815-16; lists of political appointees and debates; description and history of the Town of Brooklyn; victims of yellow fever epidemic; chronology of Brooklyn events; prices of numerous commodities.

Notes and Memoranda, Vol. 3 (Common Place Book, Vols. 3 and 4): (One volume, with Volume 3 beginning after page 128.) circa 1815-circa 1825, with addenda as late as 1845. Notes on old Brooklyn; yellow fever epidemic; partial index by Furman; a Brooklyn man's monopoly on strawberries.

Notes and Memoranda, Vol. 4: circa 1824-circa 1835. Assorted historical notes; excerpts from New York archives (1674-1737); statistics, poems, stories and anecdotes; Furman's warning (proved correct in the panic of 1837) about the dangers of speculating in Western land; Furman's disapproval of government meddling with currency.

Notes and Memoranda, Vol. 5: 1725, circa 1827-circa 1845. Appears to include an original 1725 document concerning tythes. Subjects include the law, from Dutch New York onward; books, antiquities and natural phenomena; notion that the earth may be hollow and that you can get to the center of it from the North Pole; a brief diary, 1827-1829.

Notes and Memoranda, Vol. 6: circa 1831-circa 1832, 1842. Index; list of cures; Furman's faith in Divine Providence; eloquent nature descriptions; cholera epidemic of 1832; Furman trip to Albany, 1832.

Notes and Memoranda, Vol. 7: circa 1832-circa 1840. Cholera epidemic of 1832 (continued from Volume 6); personal journal for 1833 and 1834; portents and omens of a world Furman considers seriously out of order; lower class troublemakers and rabble rousers; financial crisis of 1837; Furman's experience as a state senator, 1840; New York street scenes.

Notes and Memoranda, Vol. 8: circa 1840, with entries from 1829 and 1836. Notes from other sources, on books, census figures, commerce, ancient Egypt, superstitions and American antiquities.

Notes and Memoranda, Vol. 9: circa 1824-circa 1843. Notes from other sources on history, law, natural phenomena and the like; notes on Revolutionary era Brooklyn, from Furman's interviews with his father and others; an extensive paper on phallic worship that Furman presented to the Ethnological Society of New York.

Notes and Memoranda, Vol. 10: circa 1834-circa 1845. Primarily notes from Furman's historical research on a variety of topics; Furman's views on abolitionists and slavery; how he would really like to live his life; personal journal entries covering the winter of 1835 and all of 1836.

Notes and Memoranda, Vol. 12: circa 1828-circa 1842. Miscellaneous notes on history, law, superstitions, antiquities, books; long series of notes on different North and South American Indian antiquities; extensive early account of the death of Meriwether Lewis; journal of a trip to Canandaigua, Niagara Falls and Buffalo.

Notes and Memoranda, Vol. 15: circa 1841-circa 1847. Long excerpts from Dutch records of New Amsterdam and Revolutionary and post-Revolutionary laws of New York; miscellaneous historical notes; journal of a visit to the Tuscarora Indian reservation, Niagara Falls and Buffalo. Entries end at page 251, and the volume finishes with several hundred blank pages.

Notes and Memoranda, Vol. 16: circa 1841-circa 1842. Notes on climate change, superstitions, history; multiple entries on Dutch New Amsterdam; Furman's proposed introduction to Natural History of New York concerning book printing in New York and a signed letter (1842) from Governor William H. Seward tipped in after page 48; long excerpt from a description of explorations in the South Sea by the USS Peacock. The volume includes numerous blank pages, both interspersed with entries and at the end.

Notes and Memoranda, Vol. 17: This journal has only blank pages.

Notes and Memoranda, Vol. 18: There are no entries from Furman in this journal and the bulk consists of only blank pages. The journal has entries of 1862-1863 from William Smith Pelletreau indicating that Southampton town records of 1640 to 1660 would be transcribed in the journal. Aside from one partial entry, no such transcriptions are present.

Miscellanies (No volume number): 1854. Weather reports for each day. A lecture by Henry Ward Beecher that Furman says changed his attitude toward abolition; early Brooklyn; profiles of early residents; cholera; fires in various cities.

Notes and Memoranda Vols. 1, 11, 13, and 14: These are not in the collection and are not known to exist.

In addition to the Notes and Memoranda volumes, the collection includes both a manuscript outline or draft and a published version of Furman's Notes, Geographical and Historical, Relating to the Town of Brooklyn, on Long-Island. Other manuscripts include Furman's Ancient Chronology of New York From First Discovery to 1799 (1822), A Sketch of the History of Theatres in the United States (circa 1828), and a transcription of Jeremiah Johnson's translation of Vanderdonck's New Netherlands. The Ancient Chronology manuscript is written on pages of an account book, possibly of one John Tyler, with entries dated 1778-1781.

Finally, the collection includes several pages from a Furman letter book, principally from 1824, and a page of his legal drafts from 1823. The bulk of the correspondence consists of letters written by Furman to his father, William, who was a New York State Assemblyman away at Albany. The principal subjects of these letters concerned local perspectives on matters that would be taken up by the legislature, including Brooklyn's effort to gain a charter for a proposed Long Island Bank, the proposed act of incorporation for Brooklyn, and Furman's opposition to a proposed expansion of capital punishment in New York. Local electoral politics is also a subject of the correspondence. Among the Brooklynites mentioned in the correspondence are Alden Spooner, Leffert Lefferts, and Joseph Sprague. The three legal drafts concern breach of marriage contract, sexual assault, and trespass.