Book III chapter 10

On Mutation¹ of Verticity and of Magnetick Properties, or on alteration² in the power excited by a loadstone.

F riction with a loadstone gives to a piece of iron a verticity strong enough; not, however, so stable that the iron may not by being rubbed on the opposite part (not only with a more powerful loadstone, but with the same) be changed and deprived of all its former verticity, and indued with a new and opposite one. Take a piece of iron wire and rub each end of the wire equally with one and the same pole of a loadstone, and let it be passed through a suitable cork³ and place it on water. Then truly one end of the wire will be directed toward that pole of the earth toward which that end of the stone will not turn. But which end of the iron wire will it be? That certainly which was rubbed last. Rub the other end of this again with the same pole, and immediately that end will turn itself in the opposite direction. Again touch the former end of the iron wire only with the same pole of the loadstone as before; and that210 end, having gained the command, immediately changes to the contrary side. So you will be able to change the property of the iron frequently, and that end of the wire rules which has been touched the last. Now then merely hold the boreal pole of the stone for some time near the boreal part of the wire which was last touched, so that it does not touch, but so that it is removed from it by one, two, or even three digits⁴, if the stone have been pretty strong; and again it will change its property and will turn round to the contrary side; which will also happen (albeit rather more feebly) even if the loadstone be removed to a distance of four digits. You will be able to do the same thing, moreover, with both the austral and the boreal part of the stone in all these experiments. Verticity may likewise be acquired and changed when thin plates of gold, silver, and glass are interposed between the stone and the end of the iron or iron wire, if the stone were rather strong, even if the intermediate lamina is not touched either by the iron or the stone. And these changes of verticity take place in smelted⁵ iron. Indeed what the one pole of the stone implants⁷ and excites, the other disturbs and extinguishes, and confers a new force. For it does not require a stronger loadstone to take away the weaker and sluggish⁸ virtue⁹ and to implant⁶ the new one; nor is iron inebriated¹⁰ by the equal strength of loadstones, and made utterly¹¹ uncertain and neutral, as Baptista Porta teaches; but by one and the same loadstone, or by loadstones endowed with equal power and might, its strength is, in accordance with magnetick rules, turned round and changed, excited, repaired, or disturbed. But a loadstone itself, by being rubbed on another, whether a larger or a more powerful stone, is not disturbed from its own property and verticity, nor does it turn round toward the opposite direction in its boat, or to the other pole opposite to that to which it inclines by its own nature and implanted verticity. For strength which is innate¹² and has been implanted for a very long time abides¹³ more firmly, nor does it easily yield from its ancient holding; and that which has grown for a long time is not all of a sudden brought to nothing, without the destruction of the substance containing it. Nevertheless in a long interval¹⁴ of time a change does take place; in one year, that is to say, or two, or sometimes in a few months; doubtless when a weaker loadstone remains¹⁵ lying by a stronger one contrary to the order of nature, namely, with the northern pole of one loadstone adjoined to the northern pole of another, or the southern to the southern. For so the weaker strength gradually declines with the lapse¹⁶ of time.

1 mutation   

n.变化，变异，转变

参考例句：

• People who have this mutation need less sleep than others.有这种突变的人需要的睡眠比其他人少。
• So far the discussion has centered entirely around mutation in the strict sense.到目前为止，严格来讲，讨论完全集中于围绕突变问题上。

2 alteration   

n.变更，改变；蚀变

参考例句：

• The shirt needs alteration.这件衬衣需要改一改。
• He easily perceived there was an alteration in my countenance.他立刻看出我的脸色和往常有些不同。

3 cork   

n.软木，软木塞

参考例句：

• We heard the pop of a cork.我们听见瓶塞砰的一声打开。
• Cork is a very buoyant material.软木是极易浮起的材料。

4 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》

5 smelted   

v.熔炼，提炼（矿石）( smelt的过去式和过去分词 )；合演( costar的过去式和过去分词 )；闻到；嗅出

参考例句：

• The lead paste is smelted in a blast furnace. 铅团在鼓风炉中被溶解。 来自互联网
• Iron is taken from the earth, and copper is smelted from ore. 铁从地里挖出，铜从石中熔化。 来自互联网

6 implant   

vt.注入，植入，灌输

参考例句：

• A good teacher should implant high ideals in children.好教师应该把高尚理想灌输给孩子们。
• The operation to implant the artificial heart took two hours.人工心脏植入手术花费了两小时。

7 implants   

n.（植入身体中的）移植物( implant的名词复数 )

参考例句：

• Hormone implants are used as growth boosters. 激素植入物被用作生长辅助剂。 来自《简明英汉词典》
• Perhaps the most far-reaching project is an initiative called Living Implants From Engineering (LIFE). 也许最具深远意义的项目，是刚刚启动的建造活体移植工程 (LIFE)。 来自英汉非文学 - 生命科学 - 医学的第四次革命

8 sluggish   

adj.懒惰的，迟钝的，无精打采的

参考例句：

• This humid heat makes you feel rather sluggish.这种湿热的天气使人感到懒洋洋的。
• Circulation is much more sluggish in the feet than in the hands.脚部的循环比手部的循环缓慢得多。

9 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。

10 inebriated   

adj.酒醉的

参考例句：

• He was inebriated by his phenomenal success. 他陶醉于他显赫的成功。 来自互联网
• Drunken driver(a driver who is inebriated). 喝醉了的司机（醉酒的司机） 来自互联网

11 utterly   

adv.完全地，绝对地

参考例句：

• Utterly devoted to the people,he gave his life in saving his patients.他忠于人民，把毕生精力用于挽救患者的生命。
• I was utterly ravished by the way she smiled.她的微笑使我完全陶醉了。

12 innate   

adj.天生的，固有的，天赋的

参考例句：

• You obviously have an innate talent for music.你显然有天生的音乐才能。
• Correct ideas are not innate in the mind.人的正确思想不是自己头脑中固有的。

13 abides   

容忍( abide的第三人称单数 )； 等候； 逗留； 停留

参考例句：

• He abides by his friends. 他忠于朋友。
• He always abides by the law. 他素来守法。

14 interval   

n.间隔，间距；幕间休息，中场休息

参考例句：

• The interval between the two trees measures 40 feet.这两棵树的间隔是40英尺。
• There was a long interval before he anwsered the telephone.隔了好久他才回了电话。

15 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。

16 lapse   

n.过失，流逝，失效，抛弃信仰，间隔；vi.堕落，停止，失效，流逝；vt.使失效

参考例句：

• The incident was being seen as a serious security lapse.这一事故被看作是一次严重的安全疏忽。
• I had a lapse of memory.我记错了。