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To get a full appreciation of what this means we must turn first to some recent human inventions.

要透徹理解這句話的意義，我們應先回顧一下人類最近的幾項發明。

rising at one-foot intervals all the way to the top of the atmosphere.

并按1英尺的間隔從地面一直排列到大氣層的頂端。

but belongs to the air, travelling it may be six thousand miles to and from its northern nesting home, feeding its flown young as it flies,

在空中十分自如，可以飛行6，000英里，可以飛往北方做窩的老家，再從老家飛回；一邊飛一邊喂養會飛的雛燕，甚至在頂風時也能在氣流中滑翔，似乎氣流在幫它前進。

In his own lifetime Galileo was the centre of violent controversy;

伽利略在世時是激烈論戰的中心。

The comparable speed from the Moon is only 1.5 miles per second.

而從月球出發的相應速度只是每秒1。5英里。

for it produces a resentful animal who at a later stage may well turn man-killer.

因為這種方法訓練會使動物反感，在以后某個時期可能會變成傷人的動物。