Sentence:  Beccaria had almost stumbled on a lead to the <WSD>relationship</WSD> between electricity and magnetism when a discharge from a Leyden jar was sent transversally through a piece of watch spring steel making its ends magnetic . 
Meaning of the word marked with <WSD> tags:  a relation between people; (`relationship' is often used where `relation' would serve, as in `the relationship between inflation and unemployment', but the preferred usage of `relationship' is for human relations or states of relatedness)