B.Lachner's drawing but with English labels. It is the second part of a well known experiment to demonstrate the reversibility of the reaction of water with anhydrous copper sulfate. Driving off water from blue hydrated copper sulfate by applying heat regenerates the original anhydrous copper sulfate.
Heating of hydrous copper sulfate free icon was designed by Firkin for icons Png and presented to its users.
Firkin
3/9/2018