Definition of "lightnings"

You nimble lightnings, dart your blinding flamesInto her scornful eyes!

c. 1603–1606, William Shakespeare, “The Tragedie of King Lear”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, (please specify the act number in uppercase Roman numerals, and the scene number in lowercase Roman numerals)

For a short space of time I remained at the window watching the pallid lightnings that played above Mont Blanc and listening to the rushing of the Arve, which pursued its noisy way beneath.

1818, [Mary Shelley], “Chapter 9”, in Frankenstein; or, The Modern Prometheus. […], volumes (please specify |volume=I to III), London: […] [Macdonald and Son] for Lackington, Hughes, Harding, Mavor, & Jones