LEEUWENHOEK’S SEALS 361 
in black) wax—show an astonishing amount of detail when 
closely studied. The seal was obviously copied from Verkolje’s 
mezzotint portrait of Leeuwenhoek (1686): it shows his 
bewigged head, as there depicted, with a curtain behind, and 
even reproduces such minutiae as his little moustache. Most 
impressions, however, are faulty or badly fractured. The best 
(from which my figure here is reproduced) is on Maria’s letter 
to the Royal Society." I judge the original die to have 
measured—outside its beaded border—approximately 21 mm. 
by 18mm. But I cannot be sure, as most impressions are so 
imperfect. (The specimen figured by Carbone (1930) is 
extremely poor.) 
This seal cannot have been used by Leeuwenhoek before 
1686, when Verkolje made his mezzotint. It may therefore 
possibly help to date some of his undated letters in future. 
The artist who cut the die is not known; but he must have 
been extremely skilful, for his work reveals—on careful study 
of good impressions—a degree of accuracy in reproducing 
minute detail which is really remarkable. Unfortunately, the 
dies of all the seals are now lost. 
SIMPLEX SIGILLUM VERI 
1 See p. 98 supra. There are two seals on this letter, but only one is 
perfect. The other is distorted by a slip in impressing the wax. 
