To "get the chair"

[Sam Clements]

Over at the Straight Dope, we have yet another thread going about the
(supposed) symbolism in "The Wizard of OZ."  But that brought up a question
about the phrase "to get the chair" meaning to be sent to death in the
electric chair.

MW cites "electric chair" from 1889.  RHDAS cites "chair" as a slang
reference to the electric chair from 1895.  In the OZ thread, there is cited
a poem written by Baum and published in a Chicago newspaper in 1896, which
reads

"When McKinley gets the chair, boys,
There'll be a jollification
Throughout our happy nation
And contentment everywhere!
Great will be our satisfaction
When the "honest money" faction
Seats McKinley in the chair!

It continues at length.  You can read the entire poem at
http://www.halcyon.com/piglet/Populism.htm

My question is:  Does Baum use "the chair" as a metaphor for the electric
chair?  If so, is this the origin of the phrase "to get the chair?"