In 2016, when I retired from speaking and traveling just about everywhere, I got involved with the General Society of Mechanics and Tradesmen of the City of New York. The society has been meeting regularly since 1785. They opened, and continue to operate, the second-oldest membership library in New York City.
In 1970, when I started in the heating industry, there was a battle going on between the folks who believed in catching and controlling the air in a hydronic system by holding it inside a plain-steel compression tank, and those who thought it was best to catch the air and just get rid of it using automatic air vents and diaphragm-type compression tanks.
The question was in the Manchester Evening News, a British newspaper, and it caught my eye when I was going through my daily Google Alerts on things that have to do with heating.