# Notation $\gamma$ for Euler's constant $\gamma$.

Question. In which book or article George Boole used the notation $$\gamma$$ for Euler's constant?

Background. Today, Euler's constant is usually denoted by $$\gamma$$. In 1993 it was found out that the notation $$\gamma$$ goes back to Carl Anton Bretschneider (1808-1878) (article written in 1835). Now Glaisher writes in "On the history of Euler's constant", 1872:

"Euler’s constant (which throughout this note will be called γ after Mascheroni, De Morgan, &c.) […] It is clearly convenient that the constant should generally be denoted by the same letter. Euler used C and O for it; Legendre, Lindman, &c., C; De Haan A; and Mascheroni, De Morgan, Boole, &c., have written it γ, which is clearly the most suitable, if it is to have a distinctive letter assigned to it."

Unfortunately, Glaisher is wrong. The notation $$\gamma$$ appears nowhere in the writings of either Euler or Mascheroni. In 2011 it was discovered that De Morgan used the notation $$\gamma$$ in 1836:
The differential and integral calculus, Baldwin and Craddock, London 1836

See here

Glaisher wrote "De Morgan, Boole, &c." the advanced question is about the "&c."

• This might be a better fit for HSM Stack Exchange. Mar 12, 2019 at 4:49
• It might be a little bit problematic to link a German website dealing with this issue on a mainly English speaking site as MSE. However, as already pointed out by Theo Benedit this question would be more likely to get answered on HSM Stack Exchange and I would recommend to repost it there aswell. Mar 12, 2019 at 6:29
• For A.De Moran see The differential and integral calculus (1836), page 578. Mar 12, 2019 at 12:31