Lesson 41 Training elephants

These movements are controlled by the trainer with the metal-pointed stick,

訓練員要用有鋒利金屬尖的長棒控制它的這種舉動，

Lesson 41 Training elephants

and the trunk eventually becomes so sore that the elephant curls it up and seldom afterwards uses it for offensive purposes.

象鼻子最后疼得卷了起來，以后它就很少用鼻子去進攻了。

Lesson 42 Recording an earthquake

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

地震就像夜間的小偷，不打招呼就來了。

Lesson 42 Recording an earthquake

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

因此，有必要發明一種儀器，既不打盹兒，也不睡覺。

Lesson 42 Recording an earthquake

Some devices were quite simple.

有些裝置非常簡單。

Lesson 42 Recording an earthquake

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

例如，有一種裝置是由一些長短、粗細不同的木棒組成；就像九柱戲的木棒一樣豎立著，

Lesson 42 Recording an earthquake

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

一旦有地震，就會震動豎立在堅硬的桌子上的木棒。

Lesson 42 Recording an earthquake

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

如果地震輕微，只有不穩定的木棒倒下；

Lesson 42 Recording an earthquake

If it were severe, they all fell.

如果地震劇烈，所有的木棒都會倒下。

Lesson 42 Recording an earthquake

Thus the rods, by falling, and by the direction in which they fell,

木棒倒下的多少和倒下的方向

Lesson 42 Recording an earthquake

recorded for the slumbering scientist the strength of a shock that was too weak to waken him,and the direction from which it came.

由于地震太弱而未驚醒科學家時，就為科學家記錄下了地震的強度和地震方向。

Lesson 42 Recording an earthquake

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

但是，如果要取得真正重大的進展，需要有比這種裝置精細得多的儀器。

Lesson 42 Recording an earthquake

The ideal to be aimed at was to devise an instrument that could record with a pen on paper,

當地震發生時，它能用筆在紙上記錄下

Lesson 42 Recording an earthquake

the movements of the ground or of the table as the quake passed by.

大地和桌子的運動情況。

Lesson 42 Recording an earthquake

While I write my pen moves, but the paper keeps still.

我寫字時，筆是移動的，紙是靜止的。

Lesson 42 Recording an earthquake

With practice, no doubt, I could in time learn to write by holding the pen still while the paper moved.

毫無疑問，經過練習，我最終能夠學會筆不動而紙動來寫字。

Lesson 42 Recording an earthquake

That sounds a silly suggestion,

這聽起來似乎是一種愚蠢的想法，

Lesson 42 Recording an earthquake

but that was precisely the idea adopted in some of the early instruments (seismometers) for recording earthquake waves.

但是早期記錄地震波的儀器（測震儀）正是采用了這種思路。

Lesson 42 Recording an earthquake

But when table, penholder and paper are all moving, how is it possible to write legibly?

可是，當桌子、夾筆裝置、紙都在移動時，怎么能書寫得清楚呢？

Lesson 42 Recording an earthquake

The key to a solution of that problem lay in an everyday observation.

可以從我們的日常生活觀察中找到這個問題的答案。

Lesson 42 Recording an earthquake

Why does aperson standing in a bus or train tend to fall when a sudden start is made?

一個人站在公共汽車或火車上，當車突然開動時，他為什么會傾倒呢？

Lesson 42 Recording an earthquake

It is because his feet move on, but his head stays still.

這是因為他的腳動了，而他的頭保持著靜止。

Lesson 42 Recording an earthquake

A simple experiment will help us a little further.

再做一個簡單的實驗可以幫助我們進一步理解這個問題。

Lesson 42 Recording an earthquake

Tie a heavy weight at the end of a long piece of string.

把一個重物拴在一根長繩子的一端，

Lesson 42 Recording an earthquake

With the hand held high in the air,

把手高高舉在空中握住繩子，

Lesson 42 Recording an earthquake

hold the string so that the weight nearly touches the ground.

讓重物幾乎接觸地面。

Lesson 42 Recording an earthquake

Now move the hand to and fro and around but not up and down.

然后把手前后左右以及旋轉擺動，但不要上下擺動。

Lesson 42 Recording an earthquake

It will be found that the weight moves but slightly or not at all.

結果會發現，重物是動了，但動得很小，甚至沒動。

Lesson 42 Recording an earthquake

Imagine a pen attached to the weight in such a way that its point rests upon a piece of paper on the floor.

假定把一支筆拴在重物上，筆尖落在地板上的一張紙上，

Lesson 42 Recording an earthquake

Imagine an earthquake shock shaking the floor, the paper, you and your hand.

假定地震發生了，地板、紙、你和你的手都會動，