Vacuum in the manifold drops as engine demand increases. If you use ported vacuum you always have a vacuum signal. If you want to make adjustments it can be done using the advance pot on the distributor when you use ported vacuum.
The decreasing or waning phases are when the moon shrinks from the full moon down to the new moon (darkness). As the moon wanes during the 3rd and 4th quarters, this is a good time to prune plants, as the water table is diminishing and so less sap will flow out of the cut ends.
Plant a moonflower vine near an outdoor space that you use at night--you'll see the blooms open as dusk falls and enjoy the blooms' appealing scent. This annual grows easily, even in difficult soil, and pairs nicely with morning glory vines which bloom during the day. Moonflower seeds germinate in 4 to 10 days. By the time of the first frost, they can reach up to 15 feet. They will bloom from mid-June to mid-September.