To the end of a sprit is attached an insulator of some kind, which may be a simple ebonite rod, or sometimes a more elaborate arrangement of oil insulators, and to the lower end of this insulator is attached the aerial wire.
"Hertzian Wave Wireless Telegraphy"
John Ambrose Fleming
She knew nothing of books, this quaint old woman, and had a very antiquated taste in wall-papers; yet there would seem to be other ways of being wise, and it may indeed be held that books act too much as insulators between us and the earth, to the mysterious currents of which gnarled shapes of unlettered old men and women may be the more sensitive as lying closer to the Mother.
"The Romance of Zion Chapel [3d ed.]"
Richard Le Gallienne
In the study of electricity, conductors and insulators were recognized.
"Our Legal Heritage, 4th Ed."
S. A. Reilly