Rainbow performed on this day in 1979 at the Manning Bowl in Lynn, Massachusetts.
As with previous dates in 1979, Rainbow was touring in support of their most recent album Down to Earth. Along with a new lineup, the album had a very new sound as compared to their previous three albums.
Practically no information is available about this concert online. I look forward to people with firsthand memories coming forward.
The concert has been recorded and is in circulation online. It is, however, fairly rare.

There’s so little information available online that the actual site of the concert is debated. Setlist.fm lists it as taking place at the Main Act Concert Club. This venue was apparently part of the Harbour House Hotel, and was also known as the Harbor House. The venue was destroyed in a fire just a year after Rainbow performed (source), and while the Harbour House Hotel survived, it filed for bankruptcy not long after (source).
The Rainbow Fanclan Legacy site lists it as having taken place at the Manning Bowl. This site has a rather…unclear construction schedule, if Wikipedia is to be believed.

This stadium was built by the Works Progress Administration during the Great Depression. It had a capacity of about 17,000 (source). Wikipedia states it could hold as many as 25,000.

The main events which occurred here were football and American football and matches.
One of the most famous music events at this venue occurred when the Rolling Stones infamously began their 1966 North American tour there. Due to a thunderstorm, they were forced to cut the concert short, enraging their fans. The resultant riot was quelled by police with tear gas. The band never returned to Lynn (source).
It has been replaced after its demolition in 2005 by Manning Field, which remains on the site to this day.