Sentence:  [Isaac Newton] was obsessed with alchemy. He spent hours copying alchemical <WSD>recipes</WSD> and trying to replicate them in his laboratory. He believed that the Bible contained numerological codes. The truth is that Newton was very much a product of his time. 
Meaning of the word marked with <WSD> tags:  Any set of instructions for preparing a mixture of ingredients. (from 17th c.)