Sampson Mordan (1790-1843), the maker of this copier book, was actually a British silversmith and co-inventer of the first patented propelling mechanical pencil in 1822. Mordan later formed a partnership with Gabriel Riddle, an established stationer, and together they sold silver mechanical pencils resembling figural objects, animals, and other novelty shapes, which were (and still are) highly prized. In addition to their wildly successful pencils, they manufactured inkstands, letter balances, cedar pencils patent locks, fire proof cash boxes, deed boxes, seal presses, and these unusual leather bound portable copying presses.
A copy was made by dampening a single sheet of tissue-like paper and placing it on a newly inked original. After bookending each with a sheet of oiled paper to prevent further ink penetration, the moist tissue paper could easily absorb the ink from the freshly written original once pressure was applied. The newly made copy was thin enough to be read from both sides and it could then be sandwiched between blotter paper for drying. A successful copy was directly dependent upon the amount of time and pressure applied to each impression, and how freshly inked the original had been. Office Museum, the definitive site on antique office equipment, claims "the quality of the copies made on letter copying presses was limited by the properties of the available copying inks." The first aniline dye was invented in 1856, which roughly coincided with the earliest importation of thin papers from Japan, and this set the stage for the rise of bound letter books for safekeeping of documents.
Making multiples of any business documents and letters in the 19th century was a persistent challenge, but this began to change after the introduction of the typewriter and the improvement of greaseless carbon paper around the 1880s. Up until this period, copying presses of all shapes, sizes and styles were being developed. This advertisement for a foot lever press from a London dealer appeared in 1886.
Source: British Library
More familiar to bookbinders is the heavy iron screw press which was also used for copying office documents in the 19th century, using the same principles of water, ink and pressure. Less portable maybe, but far more industrial strength.
Source: Letterology Archives