Up until now, I pegged the pluto chips to be anywhere from 1895 to 1910. This was based, in large part, due to the construction of the chips. Paper inlays (beneath the celluloid upper layer) were done away with in 1911. I am know almost sure that the chips were made prior to 1907 (probably in 1904 to 1906). I have several great articles on how the Republicans used the pluto chips to discredit Thomas Taggart (head of the DNC in Indiana and owner of the French Lick Springs Hotel) who had the chips made.

Severally really interesting articles from Indiana, Chicago & NY describe the whole sordid mess which ended in a police raid in 1906. I also have a neat ad for the French Lick Springs Hotel.

Thanx, Dean.
Here is the link http://www.oldpokerchips.com/NonNevada/Pluto.htm