Sentence:  Again, the concretion of Ice will not endure a dry attrition without liquation ; for if it be rubbed long with a cloth, it melteth. But Cryſtal will calefie unto <WSD>electricity</WSD> ; that is, a power to attract ſtraws or light bodies, and convert the needle freely placed. 
Meaning of the word marked with <WSD> tags:  Originally, a property of amber and certain other nonconducting substances to attract lightweight material when rubbed, or the cause of this property; now understood to be a phenomenon caused by the distribution and movement of charged subatomic particles and their interaction with the electromagnetic field. (from 17th c.)