Approaching a house at night, it is possible to tell, from a distance, if the television is on. Even if the program is inaudible, the night walker, passing by, can discern beneath the sounds of wind and foliage, of cooling roof iron and cars ticking in their mechanical sleep, a kind of hum—a high and eerie keening, a dog whistle set to the human ear. The ghost in the television is electricity, pulsing at high frequency, causing the metal parts of the appliance to vibrate minutely, shaking its tiny ferrite bones.