Deep Purple performed on this day in 1968 at the Electric Circus in New York City. They played two shows.
As with the previous three shows, very little is known about the actual concerts beyond the fact that they were there and played. Hopefully that will be resolved some day!
As another point of interest, Rod Evans reportedly met the musician Emmaretta Marks at some point on the US tour. As she was part of the cast of the musical Hair, which was on broadway in 1968 (source), it could well have happened on one of these dates. Marks inspired the single “Emmaretta”, which Purple recorded in early January soon before beginning a UK tour and sessions for their third album.
I talk more about the Electric Circus, the venue at which they performed, here.