This doesn't mean you can simply go through the motions— researchers have found that merely smiling and nodding at set intervals doesn't quite work.

这并不意味着你可以简单地走走过场——研究人员发现，仅仅微笑和按固定的时间点头是行不通的。

He probably paced this out by foot, or maybe using an odometer, with wheels that turned gears that measured distance by dropping a ball into a bucket at set intervals.

他可能是用脚来测量的，或者可能是用里程表，用轮子来转动，通过在设定的时间间隔内把球扔进桶里来测量距离。