Fig. 2

Reprinted from 40: Fig. 1, p. 17 with permission from Wydawnictwo Polskiej Akademii Nauk
Drawing of a lead ingot found in 1786. The dimension (from a to b) is 3 Rhine feet, that is 84 cm (according to Wrocław’s linear measure from eighteenth century) or 93 cm (according to Prusian linear measure dated on the beginning of nineteenth century); the thickness from c to d is 8 inches that is 20 cm.