Ad from Western Electric in May 11, 1895 showing a CD 114 and touting "... where the efficiency of the Insulator has proven to be more then twice that of the ordinary Insulator, we have concluded to apply the device to all Insulators for Telegraph, Telephone, and Street Railway work..."
Courtesy of Elton Gish. Note that "colored glass insulators" are available. I suspect Amber and Peacock were two of the intentional colors. And note "Work on special designs a feature" -- what could they have made, and where are they? Lot of interesting material written in this small ad.
And so the proliferation of drip points began!
(Note also the comment about "Colored Glass Insulators to designate different currents"