It always falls down. That's how the apple helped Isaac Newton.
An 18th-century account of how Newton developed the theory of gravity was posted to the Web Monday, making the fragile paper manuscript widely available to the public for the first time.
Newton's encounter with the apple ranks among science's most celebrated anecdotes, and it can now be read in the faded cursive script in which it was recorded by William Stukeley, Newton's contemporary.
Royal Society librarian Keith Moore said the apple story has resonated for centuries because it packs in so much — an illustration of how modern science works, an implicit reference to the solar system and even an allusion to the Bible.
When Newton describes the process of observing a falling apple and guessing at the principle behind it "he's talking about the scientific method," Moore said.
"Also the shape of the apple recalls the planet — it's round — and of course the apple falling from the tree does indeed hark back to the story of Adam and Eve, and Newton as a religious man would have found that quite apt."
The incident occurred in the mid-1660s, when Newton retreated to his family home in northern England after an outbreak of the plague closed the University of Cambridge, where he had been studying.
Stukeley's manuscript recounts a spring afternoon in 1726 when the famous scientist shared the story over tea "under the shade of some apple trees."
Stukeley wrote that Newton told him the notion of gravity popped into the scientist's mind as he was sitting in the same situation.
"It was occasion'd by the fall of an apple, as he sat in contemplative mood. Why should that apple always descend perpendicularly to the ground, thought he to himself ... Why should it not go sideways, or upwards? But constantly to the earth's center?" Stukeley wrote. "Assuredly, the reason is, that the earth draws it. There must be a drawing power in matter."
Stukeley's account on the Royal Society's Web site joins notes from Newton's 17th-century scientific rival Robert Hooke — documents that were lost for several hundred years before their recent discovery in a house in England.
它總是垂直下落——蘋果正是這樣啟發了艾薩克•牛頓。
本周一，一份有關牛頓是如何發現萬有引力定律的18世紀的手稿被傳到網上，讓不易保存的紙質手稿內容首次在網上與公眾見面。
牛頓與蘋果的故事是最著名的科學軼事之一，現在這個故事竟可以在褪了色的手寫稿中讀到，這份手稿的內容是由與牛頓同時代的(科學家)威廉•斯蒂克利記錄的。
皇家學會圖書館館長基斯•摩爾說，蘋果落地的故事已經流傳了幾個世紀，因為它的意義十分重大——它不僅奠定了現代科學的根基，暗示了太陽系的運行原理，甚至還暗指了《聖經》。
摩爾說，當牛頓描述觀察蘋果落地的過程並猜想其背後的原理時，「他說的是科學方法」。
「此外，蘋果的形狀讓人想到地球，它是圓的，當然從樹上掉下的蘋果的確會讓人想起亞當和夏娃的故事，信奉宗教的牛頓自然覺得這很合理。」
蘋果落地事件發生於17世紀60年代中期，當時由於瘟疫的爆發使得牛頓就讀的劍橋大學停課，牛頓只好回到他在英格蘭北部的家中。
斯蒂克利的手稿講述了1726年春天的一個下午，這位著名的科學家坐在「幾棵蘋果樹的綠蔭下」一邊喝茶，一邊與他分享了這個故事。
斯蒂克利在手稿中寫道，牛頓告訴他，自己也是坐在蘋果樹下，靈機一閃，產生了萬有引力的想法。
「當時他正坐在蘋果樹下思考問題，突然一隻蘋果從樹上掉下，讓他產生了這一想法。他心想，為什麼蘋果總是垂直落到地面?為什麼它不向旁邊落下，或是向上，而總是落到正中央的位置?」斯蒂克利寫道，「這一定是因為地球在吸引它。一定存在著某種吸引力。」
除斯蒂克利的這篇手稿外，皇家學會網站上還登載了17世紀牛頓的學術對手羅伯特•胡克的一些科學記錄，這些資料已失蹤數百年，前不久在英國的一所房子裡找到。
Vocabulary:
cursive:Having the successive letters joined together: 草書的：連續的字母連在一起的
hark back to: to remind you of, or to be like, something in the past 使想起
retreat: to escape to a place that is quieter or safer 隱退
perpendicularly: in a perpendicular manner 垂直地