Dry Cosmic Hiss

Although Falkayn attempts radio communication with a pursuing Shenn battleship:

"...nothing spoke to Falkayn save a dry cosmic hiss." (Chapter XVII, p. 509) (For full reference, see here.)

This "dry cosmic hiss" joins the "dry whisper" and the "dismal universal hiss" of previous quotations. See Cosmic Interference. Those earlier quotations are from Poul Anderson and from James Blish quoting John Milton.