The late seventies were an interesting time for the Chemex coffeemaker. It was still a popular design object, of course, AND it was still known to be a great way to brew coffee. But it faced competition from the increasing popularity and accessibility of automatic drip coffee makers, and in the 1980s the French press exploded on the scene. It wasn't until 2010 and beyond, with the resurgent coffee culture, that the Chemex began regaining its standing as a coffeemaker of choice.
Here are the pages with brewing instructions. If you were intimidated out of using a Chemex by the intensity and precision of today's coffee aficionados, these friendly 1970s instructions should allow you to relax a bit and just enjoy a damn cup of coffee.