Rontgen could not see anything coming out of the tube, but then he discovered that if he put the screen in the next room on the other side of a closed door, the rays still seemed to affect it.

• 伦琴无法用肉眼看到射出的东西，但当他将屏幕移入隔壁房间的另一边并关上房门，此射线似乎仍能对屏幕产生影响。