And then further you put some recording device, which in those days was a photographic plate, far across a room. So you take a tiny, tiny angle and you go far enough across the room.

接着放一些记录设备，那时用的是一个摄影用的感光片，取一个极小极小的角度,然后去到房间中足够远的地方。

麻省理工公开课 - 固态化学导论课程节选