If it is not indeed a relic of the Napoleonic era, it is at least drinkable.
"The Box with the Broken Seals"
E. Phillips Oppenheim
Duchemin stopped and waited for the other to come up, thinking to get a better look at him, perhaps some definite information about the road and in particular as to his chances of finding drinkable water.
"Alias The Lone Wolf"
Louis Joseph Vance
I determined to speak to him still worse the next day; but as soon as he appeared my anger cooled, for before giving me the account of my money he presented me with a basket of lemons which M. de Bragadin had sent me, also a large bottle of water, which seemed drinkable, and a nice roasted fowl; and, besides this, one of the guards opened the two windows.
"The Memoires of Casanova, Complete The Rare Unabridged London Edition Of 1894, plus An Unpublished Chapter of History, By Arthur Symons"
Jacques Casanova de Seingalt