$课文42 记录地震

792. An earthquake comes like a thief in the night, without warning.

地震就像夜间的小偷，不打招呼就来了。

793. It was necessary, therefore, to invent instruments that neither slumbered nor slept.

因此，有必要发明一种仪器，既不打盹儿，也不睡觉。

794. Some devices were quite simple.

有些装置非常简单。

795. One, for instance, consisted of rods of various lengths and thicknesses with would stand up end like ninepins.

例如，有一种装置是由一些长短、粗细不同的木棒组成，就像九柱戏的木棒一样坚立着，

796. When a shock came, it shook the rigid table upon which these stood.

一旦有地震，就会震动竖立在坚硬的桌上的木棒。

797. If it were gentle, only the more unstable rods fell.

如果地震轻微，只有不稳定的木棒倒下；

798. If it were severe, they all fell.

如果地震剧烈，所有的木棒都会例下。

799. Thus the rods, by falling, and by the direction in which they fell, recorded for the slumbering scientist the strength of a shock that was too weak to waken him, and the direction from which it came.

由于地震太弱而未惊醒科学家时，木棒倒下的多少和倒下的方向就为科学家记录下了地震的强度和地震方向。

800. But instruments far more deliecate than that were needed if any really serious advance was to be made.