7ª Bienal do Mercosul

To Johann Beckmann

Honoured wellborn [aristocratic greeting]

I can now report reliably (since I heard it myself from HE. DeLuc) that London is plastered partially in basalt and partially in granite. The former comes from Scotland, but the latter from the isles of Jersey and Guernsey.

Could honoured wellborn not tell me, where the forms of our paper makers are produced, or whether they, which I doubt, make their own? The reason for this question may not be uncomfortable for honoured wellborn. I once gave an exercise to a young Englishman, whom I taught in algebra, to find a sheet of paper for which all formats forma patens, folio, 4to, 8, 16, are similar to each other. Having found that ratio, I wanted to apply it to an available sheet of ordinary writing paper with scissors, but found with pleasure, that it already had it. It is the paper on which I write this letter, but to which, because since by cutting some of its original form may have been lost, I also add an uncut original. The short side of the rectangle must relate to the large one like 1 : ‚àö2, or like the side of a square to its diagonal.*

This form has something pleasant and distinguished before the ordinary [form]. Are these rules given to the paper makers or has this form spread through tradition? Where does this form come from, which appears not to have emerged by accident?

Honoured wellborn forgive me this freedom.

[Göttingen,] 25. Oct. 1786

GCLichtenberg

* the modern DIN format is based on this ratio, which remains the same with each subsequent halving (or doubling). L. reports detailed in GTC 1796, 171 (Schriften 6, 1845, 266). However, he cannot claim priority for this discovery: A. G. Kästner told Dorothea Schlözer, who solved this problem in 1787 when it was presented to her in her doctoral examination, that the master B. (Butschany ?) was not able to solve it in his examination (around 1755) (L. v. Schlöser, Dorothea von Schlözer, 1937, 129).