Green spectacles

[Benjamin Barrett]

In Mark Twain's Innocents Abroad, the passengers wear green spectacles.
I remember that L. Frank Baum also has the Wizard of Oz telling the
inhabitants of the Emerald City that they had to wear green spectacles
or the emeralds of the city would blind them (but it was actually
because there were no emeralds).

I assume green spectacles were just the state of the art for sunglasses,
but can anyone affirm that or say if there is something of importance
about them?

I also found the following on the Web about Baum's story...

Baum develops a popular column, "Our Landlady," that takes place in a
fictitious boarding house run by Sairy Ann Bilkins, a widow and
busybody. There boarders discuss the issues and personalities important
to life in Aberdeen. "Our Landlady" also includes some of Baum's
earliest fantasy writing; columns speak of horseless carriages, flying
machines, mechanical dishwashers, electric blankets and concentrated
foods. In one issue a farmer reports he has his horses wear green
spectacles so they'll think they are eating grass instead of wood
shavings. The whimsy foreshadows Baum's original Emerald City of Oz
where citizens and guests are issued green glasses at the entrance. "Our
Landlady" continues for 48 columns of satire, broad comedy and
effectively entertainment and criticism of his fellow Aberdonians. The
column may have been modeled after a similar column in the Syracuse
Standard of 1884 or others of the genre.

Benjamin Barrett