In the 24 June 2004 issue of London Rev of Books (review of The Bugatti Queen [about an early auto race driver] by the prolific Miranda Seymour) there's mention of an ad for "the Gabriel horn: 'Everywhere you are greeted by the clear sweet note of the finest auto horn in the world.'" Could TSE have seen the ad and incorporated it (slightly, to be sure) into TWL ("horns and motors" with undertone of the angel Gabriel?) as he did the "pneumatic" tyre ads in "Whispers of Mortality"?  --  All best to the list,   --  Jim Loucks