The Four Great Inventions
四大发明
The Compass
指南针
A compass can be any magnetic device using a needle to indicate the direction of the magnetic north of a planet’s magnetosphere.
指南针之任何一个带有指向星球磁场中磁北的指针的磁性装置。
Any instrument with a magnetized bar or needle turning freely upon a pivot and pointing in a northerly and southerly direction can be considered a compass.
任何带有以中心点旋转并指向北方的磁棒或指针地工具都被认为是指南针。
A compass dial is a small pocket compass with a sundial.
罗盘刻度盘是一个带有日晷的小型口袋指南针。
A variation compass is a specific instrument of a delicate type of construction.
变异指南针是精妙建筑上的一个特别的工具，通过观察针的变化来工作，回转罗盘或天文罗盘同样可以被用来确定真正的北方。
It is used by observing variations of the needle, a gyrocompass or astrocompass can also be used to ascertain true North.
罗盘在中国古代首先被运用于风水中。
Compasses were initially used in feng shui (风水）in ancient China.
它已知的第一次在中国古代的地球磁场中的运用是作为一个景观。
The first known use of Earth's magnetic field in this way occurred in ancient China as a spectacle.
箭头像骰子一样被投掷。
Arrows were cast similarly to dice.
磁化的箭头一致指向北方，这样的场景给观众们留下了深刻印象。
These magnetized arrows aligned themselves pointing north, impressing the audience.
磁石作为一个指向标的用法首次被记载在中国公元前4世纪的书籍《鬼谷子》中。
The earliest record of use of magnetic lodestone as a direction point was in a 4th century BC Chinese book: “Book of the Devil Valley Master”.
宋朝学者沈括于1068年写的《梦溪笔谈》一书中详细记载了风水师是如何通过用磁石摩擦指针的尖端而使其磁化，接着用一段拉紧的丝绸将磁针悬挂起来，丝绸上的蜡与磁针的中心点相连。
“Dream Pool Essays” written by Song Dynasty scholar Shen Kuo in 1086 AD contained a detailed description of how geomancer magnetized a needle by rubbing its tip with lodestone, and hanged the magnetic needle with one single strain of silk with a bit of wax attached to the center of the needle.
沈括指出经过这种处理的磁针有时指向男方有时指向北方。
Shen Kuo (沈括）pointed out that the needle prepared this way some times pointed south, some times pointed north.
指南针在航海中的运用最早被记录在公元1117年时朱彧的《萍洲可谈》。
The earliest record about the use of compass in navigation was Zhu Yu's book “Pingzhou Ke Tan” (Pingzhou Table Talks) of 1117 AD.
航海家了解地理，他夜观星象，白天观察太阳，当天色很暗或是阴天时，他就观察指南针。
The navigator knows the geography, he watches the stars at night, watches the sun at day; when it is dark and cloudy, he watches the compass.
指南针的只是流传到阿拉伯地区，接着在12世纪传入欧洲。
Knowledge of the compass moved overland through the Arab countries and then to Europe sometime later in the 12fh century.
比如，指南针在《Luba ul-Albab》一书中被记载和形容在1220年左右用于航海。
The compass, for example, is described and reported being used in the book Luba ul-Albab for purposes of sea navigation around 1220.
1358年左右有一个关于英国僧人的故事，他因为能够熟练使用罗盘而成为了一名航海员。
About 1358，there is a story about an English monk, Nicholas of Lynne, who served as a navigator due to his competence and knowledge in the “magnetic compass”.
在指南针出现以前，海上的寻路原先都通过天文导航，在有些地方它被作为水路测探的补充。
Prior to the introduction of the compass, wayfinding at sea was primarily done via celestial navigation, supplemented in some places by the use of soundings.
当谋篇海域深度过深或者周围的天气是阴天和雾天时，探测就变得非常困难。
Difficulties arose where the sea was too deep for soundings and conditions were continually overcast or foggy.
因此，指南针在不同的地区具有不同的效用。
Thus the compass was not of the same utility everywhere.
例如，阿拉伯人通常依赖于晴朗的天空在波斯湾和印度洋中导航（同样还通过季风的可预测性）。
For example, the Arabs could generally rely on clear skies in navigating the Persian Gulf and the Indian Ocean (as well as the predictable nature of the monsoons).
这也许能够部分解释他们对于指南针相对较晚的使用。
This may explain in part their relatively late adoption of the compass.
相对浅的波罗的海地区的水手就广泛运用测探。
Mariners in the relatively shallow Baltic made extensive use of soundings.
然而，在地中海地区，从远古时代开始的惯例就是在10月到4月间减少海上活动，部分原因在于地中海的冬季没有当地人可依赖的晴朗天空（大部分海域对于探测来说过深了）。
In the Mediterranean, however, the practice from ancient times had been to curtail sea travel between October and April, due in part to the lack of dependable clear skies during the Mediterranean winter (and much of the sea is too deep for soundings).
当位置推算法和更好的图表不断发展后，这种情况在13时期的下半期改变了。
With improvements in dead reckoning methods, and the development of better charts, this changed during the second half of the 13th century.
1290年左右，出海的季节可以从1月底或2月开始，于12月结束。
By around 1290 the sailing season could start in late January or February, and end in December.
这多出来的几个月对于经济来说相当重要；比如，它使威尼斯商队在一年中两次而不是一次往返于东地中海地区。
The additional few months were of considerable economic importance; it enabled Venetian convoys, for instance, to make two round trips a year to the eastern Mediterranean, instead of one.
同时，地中海和北欧之间的交通运输增加了，也许是比斯开湾上的航行更加安全和便利的指南针是其中一个原因。
Around the same time traffic between the Mediterranean and northern Europe increased, and one factor may be that the compass made traversal of the Bay of Biscay safer and easier
。