The manuscripts in the collection consist of fifty-two letters written by thirty-seven scientists. They are arranged alphabetically by writer and date between 1677 and 1873. Among those which discuss scientific projects and topics is a letter, written in 1772, from Edward Bancroft (1744-1821) to Sir Joseph Banks (1743-1820) about preserving ships' timbers from the ravages of 'aquatic worms'. Another, 1823, from Sir John Herschel (q.v.) to Pierre Simon, Marquis de la Place (1749-1827) is concerned with Sir William Herschel's discovery of the distances and position of the double stars and the series of experiments, using binary systems, carried out by Sir John to verify the discovery. Astronomy is again the subject of a letter of 1854 from Sir George Airy (1801-1892) to Urbain Le Verrier (1811-1877) on the arrangement of an apparatus for the galvanic register of observations, simultaneously at Greenwich and Paris, for the determination of longitude. The majority of documents in this collection have, however, been collected for their autograph value. Other than the prominent scientists mentioned above, the letters include those by William Brouncker (1620-1684), 1677 and 1685; John Flamstead (1646-1719), 1695 and 1703; Nevile Maskelyne (1732-1811), 1784; Joseph Priestly (1733-1804), 1772; William Scoresby (1789-1857), 1827 and Michael Faraday (1791-1867), 1857.

Administrative / biographical background
For some fifty years George H. Gabb (fl.1880-1930) built up a collection not only of manuscripts relating to science but also of scientific instruments.