...the worn, fading envelope...(Para. 16)
fade: vi. 1) (cause to) lose color or freshness 褪色
Her dark blue skirt was so old that it had faded to light blue. 她那条深兰的裙子很旧了,颜色已褪成浅蓝色了。
2) disappear bit by bit 逐渐消失
His strength seemed to fade after the operation. 手术以后,他似乎觉得越来越没有力气了。
The music from the radio slowly faded away. 乐队的音乐渐渐地消失了。
As we drove into the mountains, the radio signal faded. 当我们驶进山区时,无线电信号渐渐减弱了。
n. 信号,标志
v. (发信号)通知、表示<