Book II Chapter 5

Chap. v.
How the Power dwells in the Loadstone.

T hat a loadstone attracts loadstone, iron and other magnetical bodies, has been shown above in the previous book, and also with what strength the magnetick coition is ordered; but now we must inquire how that vigour¹ is disposed in a magnetick substance. And indeed an analogy must be inferred from a large loadstone. Any magnetick substance joins itself with a loadstone strongly, if the loadstone itself is strong; but more weakly, when it is somewhat imperfect or has been weakened by some flaw. A loadstone does not draw iron equally well with every part; or a magnetick substance does not approach every part of a loadstone alike; because a loadstone has its points, that is its true poles, in which an exceptional virtue² excels. Parts nearer the pole are stronger, those far away more weak, and yet in all the power is in a certain way equal. The poles of a terrella are A, B; the æquinoctial is C, D. At A and B the alluring³ force seems greatest.



At C and D there is no force alluring magnetick ends to the body, for the forces tend toward both poles. But direction is powerful on the æquator. At C, D, the distances are equal from both poles; therefore iron which is at C, D, when it is allured⁴ in contrary ways, does not adhære with constancy; but it remains⁵ and is joined to the stone, if only it incline to the one or other side. At E there is a greater power of alluring than at F, because E is nearer the pole. This is not so because there is really greater virtue residing at the pole, but since all the parts are united in the whole, they direct their forces towards the pole. From the forces flowing from the plane of the æquinoctial towards the pole, the power increases. A fixed⁶ verticity exists at the pole, so long as the loadstone remains whole; if it is divided or broken, the verticity obtains other positions in the parts into which it is divided. For the verticity always changes in consequence of any change in the mass, and for this cause, if the terrella be divided from A to B, so that there are two stones, the poles will not be A, B, in the divided parts, but F, G, and H, I.



Although these stones now are in agreement with one another, so that F would not seek H, yet if A was previously⁷ the boreal pole163, F is now boreal, and H also boreal; for the verticity is not changed (as Baptista Porta incorrectly affirms in the fourth chapter of his seventh book); since, though F and H do not agree, so that the one would incline to the other, yet both turn to the same point of the horizon. If the hemisphere H I be divided into two quadrants, the one pole takes up its position in H, the other in I. The whole mass of the stone, as I have said, retains the site of its vertex constant; and any part of the stone, before it was cut out from the block164, might have been the pole or vertex. But concerning this more under Direction. It is important now to comprehend and to keep firmly in mind that the vertices are strong on account of the force of the whole, so that (the command being, as it were, divided by the æquinoctial) all the forces on one side tend towards the north; but those of an opposite way towards the south, so long as the parts are united, as in the following demonstration⁸.


For so, by an infinite number of curves from every point of the equator dividing the sphere into two equal parts, and from every point of the surface from the æquator towards the North, and from the æquator towards the Southern pole, the whole force tends asunder⁹ toward the poles. So the verticity is from the æquinoctial circle towards the pole in each direction. Such is the power reposed¹⁰ in the undivided stone. From A vigour is sent to B, from A, B, to C, from A, B, C, to D, and from them likewise to E. In like manner from G to H, and so forth¹¹, as long as the whole is united. But if a piece A B be cut out (although it is near the æquator), yet it will be as strong in its magnetical actions as C D or D E, if torn away from the whole in equal quantity. For no part excels in special worth in the whole mass except by what is owing to the other adjoining parts by which an absolute and perfect whole is attained¹².

Diagram of Magnetic Vigour transmitted from
the plane of the Æquator to the peripherery of
the terella or of the earth

HEQ is a terrella, E a pole, M the centre, HMQ the æquinoctial plane. From every point of the æquinoctial plane vigour extends to the periphery¹³, but by various methods; for from A the formal force is transmitted towards C, F, N, E, and to every point from C up to E, the pole; but not towards B; so neither from G towards C. The power of alluring is not strengthened in the part FHG from that which is in GMFE, but FGH increases the force in the eminence¹⁴ FE. So no force rises from the internal parts, from the lines parallel to the Axis¹⁵ above those parallels, but always inwards from the parallels to the pole. From every point of the plane of the equator force proceeds to the pole E, but the point F has its powers only from GH, and N from OH; but the pole E is strengthened from the whole plane HQ. Wherefore in it the mighty¹⁶ power excels (just as in a palace); but in the intermediate intervals¹⁷ (as in F) only so much force of alluring is exerted as the portion HG of the plane can contribute.

1 vigour   

（=vigor）n.智力，体力，精力

参考例句：

• She is full of vigour and enthusiasm.她有热情，有朝气。
• At 40,he was in his prime and full of vigour.他40岁时正年富力强。

2 virtue   

n.德行，美德；贞操；优点；功效，效力

参考例句：

• He was considered to be a paragon of virtue.他被认为是品德尽善尽美的典范。
• You need to decorate your mind with virtue.你应该用德行美化心灵。

3 alluring   

adj.吸引人的，迷人的

参考例句：

• The life in a big city is alluring for the young people. 大都市的生活对年轻人颇具诱惑力。
• Lisette's large red mouth broke into a most alluring smile. 莉莎特的鲜红的大嘴露出了一副极为诱人的微笑。

4 allured   

诱引，吸引( allure的过去式和过去分词 )

参考例句：

• They allured her into a snare. 他们诱她落入圈套。
• Many settlers were allured by promises of easy wealth. 很多安家落户的人都是受了诱惑，以为转眼就能发财而来的。

5 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

6 fixed   

adj.固定的，不变的，准备好的；(计算机)固定的

参考例句：

• Have you two fixed on a date for the wedding yet?你们俩选定婚期了吗？
• Once the aim is fixed,we should not change it arbitrarily.目标一旦确定，我们就不应该随意改变。

7 previously   

adv.以前，先前（地）

参考例句：

• The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
• Let me digress for a moment and explain what had happened previously.让我岔开一会儿，解释原先发生了什么。

8 demonstration   

n.表明，示范，论证，示威

参考例句：

• His new book is a demonstration of his patriotism.他写的新书是他的爱国精神的证明。
• He gave a demonstration of the new technique then and there.他当场表演了这种新的操作方法。

9 asunder   

adj.分离的，化为碎片

参考例句：

• The curtains had been drawn asunder.窗帘被拉向两边。
• Your conscience,conviction,integrity,and loyalties were torn asunder.你的良心、信念、正直和忠诚都被扯得粉碎了。

10 reposed   

v.将（手臂等）靠在某人（某物）上( repose的过去式和过去分词 )

参考例句：

• Mr. Cruncher reposed under a patchwork counterpane, like a Harlequin at home. 克朗彻先生盖了一床白衲衣图案的花哨被子，像是呆在家里的丑角。 来自英汉文学 - 双城记
• An old man reposed on a bench in the park. 一位老人躺在公园的长凳上。 来自辞典例句

11 forth   

adv.向前；向外，往外

参考例句：

• The wind moved the trees gently back and forth.风吹得树轻轻地来回摇晃。
• He gave forth a series of works in rapid succession.他很快连续发表了一系列的作品。

12 attained   

（通常经过努力）实现( attain的过去式和过去分词 )； 达到； 获得； 达到（某年龄、水平、状况）

参考例句：

• She has attained the degree of Master of Arts. 她已获得文学硕士学位。
• Lu Hsun attained a high position in the republic of letters. 鲁迅在文坛上获得崇高的地位。

13 periphery   

n.(圆体的)外面；周围

参考例句：

• Geographically, the UK is on the periphery of Europe.从地理位置上讲，英国处于欧洲边缘。
• The periphery of the retina is very sensitive to motion.视网膜的外围对运动非常敏感。

14 eminence   

n.卓越，显赫；高地，高处；名家

参考例句：

• He is a statesman of great eminence.他是个声名显赫的政治家。
• Many of the pilots were to achieve eminence in the aeronautical world.这些飞行员中很多人将会在航空界声名显赫。

15 axis   

n.轴，轴线，中心线；坐标轴，基准线

参考例句：

• The earth's axis is the line between the North and South Poles.地轴是南北极之间的线。
• The axis of a circle is its diameter.圆的轴线是其直径。

16 mighty   

adj.强有力的；巨大的

参考例句：

• A mighty force was about to break loose.一股巨大的力量即将迸发而出。
• The mighty iceberg came into view.巨大的冰山出现在眼前。

17 intervals   

n.[军事]间隔( interval的名词复数 )；间隔时间；[数学]区间；（戏剧、电影或音乐会的）幕间休息

参考例句：

• The forecast said there would be sunny intervals and showers. 预报间晴，有阵雨。
• Meetings take place at fortnightly intervals. 每两周开一次会。