Book IV chapter 10

Why in various places near the pole the variations are much more ample than in a lower latitude¹.

V ariations are often slight, and generally null, when the versorium is at or near the earth's æquator. In a higher Latitude of 60, 70 or 80 deg. there are not seldom very wide variations. The cause of this is to be sought partly from the nature of the earth and partly from the disposition² of the versorium. The earth turns magnetick bodies and at the æquator directs them strongly toward the pole: 227at the poles there is no direction, but only a strong coition through the congruent poles. Direction is therefore weaker near the poles, because by reason of its own natural tendency to turn, the versorium dips very much, and is not strongly directed. But since the force of those elevated lands is more vigorous, for the virtue³ flows from the whole globe, and since also the causes of variation are nearer, therefore the versorium deflects⁴ the more from its true direction toward those eminences⁵. It must also be known that the direction of the versorium on its pin along the plane of the Horizon is much stronger at the æquator than anywhere else by reason of the disposition of the versorium; and this direction falls off with an increase of latitude. For on the æquator the versorium is, following its natural property, directed along the plane of the horizon; but in other places it is, contrary to its natural property, compelled into æquilibrium, and remains⁶ there, compelled by some external force: because it would, according to its natural property, dip below the horizon in proportion to the latitude, as we shall demonstrate in the book On Declination. Hence the direction falls off and at the pole is itself nothing: and for that reason a feebler direction is easily vanquished⁷ by the stronger causes of variation, and near the pole the versorium deflects the more from the meridian⁸. It is demonstrated by means of a terrella: if an iron wire of two digits⁹ length be placed on its æquator, it will be strongly and rapidly directed toward the poles along the meridian, but more weakly so in the mid-intervals; while near the poles one may discern a precipitate¹⁰ variation.

1 latitude   

n.纬度，行动或言论的自由(范围)，(pl.)地区

参考例句：

• The latitude of the island is 20 degrees south.该岛的纬度是南纬20度。
• The two cities are at approximately the same latitude.这两个城市差不多位于同一纬度上。

2 disposition   

n.性情，性格；意向，倾向；排列，部署

参考例句：

• He has made a good disposition of his property.他已对财产作了妥善处理。
• He has a cheerful disposition.他性情开朗。

3 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。

4 deflects   

（使）偏斜， （使）偏离， （使）转向( deflect的第三人称单数 )

参考例句：

• This love is so bright that it deflects all darkness. 这个爱如此光明而可以照亮黑暗。
• Level 3-Deflects 15% of damage taken onto a 600 AoE. 三级-将15%的所受伤害反弹给600范围内的所有敌方单位。

5 eminences   

卓越( eminence的名词复数 )； 著名； 高地； 山丘

参考例句：

• Both are truly grey eminences who have become accustomed to the exercise of influence. 两个人都是真正的幕后操纵者，他们已习惯于用其影响进行幕后操纵。

6 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。

7 vanquished   

v.征服( vanquish的过去式和过去分词 )；战胜；克服；抑制

参考例句：

• She had fought many battles, vanquished many foes. 她身经百战，挫败过很多对手。 来自《简明英汉词典》
• I vanquished her coldness with my assiduity. 我对她关心照顾从而消除了她的冷淡。 来自《现代英汉综合大词典》

8 meridian   

adj.子午线的；全盛期的

参考例句：

• All places on the same meridian have the same longitude.在同一子午线上的地方都有相同的经度。
• He is now at the meridian of his intellectual power.他现在正值智力全盛期。

9 digits   

n.数字( digit的名词复数 )；手指，足趾

参考例句：

• The number 1000 contains four digits. 1000是四位数。 来自《简明英汉词典》
• The number 410 contains three digits. 数字 410 中包括三个数目字。 来自《现代英汉综合大词典》

10 precipitate   

adj.突如其来的；vt.使突然发生；n.沉淀物

参考例句：

• I don't think we should make precipitate decisions.我认为我们不应该贸然作出决定。
• The king was too precipitate in declaring war.国王在宣战一事上过于轻率。