Eberhard Faber No. 2 3/8

Vladimir Nabokov, Bend Sinister (1947).

Eberhard Faber No. 2 3/8? That would be a Mongol.

Why that improbable fraction? Henry Petroski’s The Pencil: A History of Design and Circumstance (1990) explains:

To this day the names of companies are confusing, and much of that confusion can be traced back to the intense competition of the nineteenth century that led to fierce battles for distinctive trademarks, as well as to deliberate confusion. Even family-related concerns separated by an ocean could not escape the problems of protecting their identities from each other. Finer and finer distinctions between pencils and their markings began to appear, and the Mongol pencil of Eberhard Faber was among the first products in the United States to have a trademark. Questions of proprietary rights led eventually to such awkward designations of pencil hardnesses as 2 1/2, 2 4/8; and 2 5/10, not to mention the decimal 2.5, as the arithmetical inclination to simplify fractions clashed with trademark protection laws.

And yes, Nabokov cared about pencils.

Related reading
All OCA Mongol posts : Nabokov posts (Pinboard)