At first glance this document makes little sense: what looks like a title line, written in a large hand and dated to the hour, is centered above two stanzas that have nothing to do with either the title or one another. Both verses are taken from the works of Joseph Addison, and the misquotations suggest that they were written from memory. Indeed, the poetry in this case was merely a vehicle for the medium. On this sheet, Franklin was conducting an experiment with writing ink, and we conjecture that he was trying to duplicate the copying ink that James Watt had patented for use with his copy presses.

From the time that James Woodmason first solicited Franklin’s subscription for Watt’s new copy presses,8 Franklin seems to have recognized what Watt knew very well: the inventor’s achievement lay not with the machine (which was a typical press), but with the procedure.9 Franklin told Woodmason that he would order three presses because of his desire to “encourage Ingenuity,” but let the stationer know that he was not intending to keep one for himself. In fact, he continued, he had already produced some copies without any special equipment, and enclosed one. Woodmason replied that Franklin’s copy would not “stand any time,” whereas “ours will stand as long as the original.”1 This, indeed, was the critical problem that Watt believed he had solved: devising an ink which, when moistened and forced into a second sheet, would remain legible over time.2

The three copy presses arrived at Passy in February, 1781. Despite his earlier statement, Franklin did keep one for his office; he also offered one to Congress. When he got word from Samuel Huntington that he should send a copying machine to Secretary of Congress Charles Thomson, he had his own copy press duplicated by a Parisian carpenter.3

Finding local sources for the copy press accessories was very much on Franklin’s mind in the summer of 1781. He had ordered more copying paper, ink powder, oiled paper, and wetting and drying books from Woodmason in May, which arrived in July with a Mr. Laurent.4 In early August Temple told Jonathan Williams, Jr., that they had found a French paper (papier de soie) that worked just as well as the English copying paper, and he was sending a ream.5 It seems reasonable that Franklin was trying to devise an ink recipe that would free him from having to rely on shipments from London of Watt’s “Patent Copying Powder.”

Was loaf sugar, the subject of the present document’s experiment, Watt’s secret ingredient? Not according to his patent, dated February 4, 1780, which reveals his formula to be a combination of Aleppo galls, green copperas, gum arabic, and roach alum.6 But Watt did try adding sugar before he settled on his final recipe, having observed that both sugar and gum helped tannin ink to offset.7 This was evidently not a new observation, and the fact that Franklin was adding sugar to French encre ordinaire (also a gall-based ink), shows that he was reasoning along the same lines.8

Whether Franklin was pleased with the results of this experiment is not known; we have found no other references in his papers to copying ink, nor any allusions (other than the press copies themselves) to the process. But the order Franklin submitted to Woodmason for copying ink and paper in May, 1781, seems to be the last such invoice for personal use that survives. His final order, of October 5, 1781, was for three complete sets of copying supplies that Franklin intended to ship to Congress along with the presses that he was having built in Paris.9

When Watt’s patent expired, his secrets were revealed to the world. The text of that patent, as well as the plate which we reproduced in volume 33, was published in the inaugural volume of The Repertory of Arts and Manufactures: consisting of Original Communications, Specifications of Patent Inventions, and Selections of Useful Practical Papers from the Transactions of Philosophical Societies of All Nations, &c. &c. (London, 1794). In time, because of the proliferation of copy presses in the nineteenth century, Watt’s ink recipe came to be commonly reprinted without attribution. Colin Mackenzie’s immensely popular Five Thousand Receipts in All the Useful and Domestic Arts reproduced it verbatim under the heading, “A Fine Black Ink, for Common Purposes, and for the Copying Press.”1 Mackenzie also included the following instructions, showing that Franklin’s idea survived as a viable alternative to Watt’s ink for decades.

Substitute for Copying Machines

In the common ink used, dissolve lump sugar (one dracham to one ounce of ink). Moisten the copying paper, and then put it in soft cap paper to absorb the superfluous moisture.— Put the moistened paper on the writing, place both between some soft paper, and either put the whole in the folds of a carpet, or roll upon a roller three or four times.2