The Crackled Boiling
Is proved by letting it boil somewhat longer; and then dipping a Stick into the Sugar, which immediately remove into a Pot of cold Water standing by you for that Purpose, drawing off the Sugar that cleaves to the Stick, and if it becomes hard, and will snap in the Water, it is enough; if not, you must boil it till it comes to that Degree.
Note, Your Water must be always very cold, or it will deceive you.