CHAPTER IX. PRESERVATION OF TIMBER. 1808–1843.

In 1808 Mr. Stevenson was the discoverer of the Limnoria terebrans, that small but sure destroyer of timber structures exposed to the action of the sea, and forwarded specimens¹ of the insect and of the timber it had destroyed to Dr. Leach², the eminent³ naturalist⁴, of the British Museum, who, in 1811, announced it as a “new and highly interesting species which had been sent to him by his friend Robert Stevenson, Civil Engineer,” and assigned to it the name of Limnoria terebrans (Linnean Trans., vol. xi. p. 37, and Edinburgh Encylop?dia, vol. vii. p. 433).

The Teredo navalis, which is a larger and even more destructive enemy, is happily not so prevalent in northern seas as the Limnoria.

So impressed was Mr. Stevenson with the importance of his discovery as affecting marine⁵ engineering, and especially harbour works, that he resolved to establish a train of systematic⁶ experiments by exposing the timber of different trees to the action of salt water, and it occurred to him that no situation could be more suitable156 for such observations than the Bell Rock, where the specimens would not only be fully⁷ exposed to the sea, and free from any interference, but would be strictly⁸ watched and minutely reported on by the lightkeepers. He further conceived it proper, in the interests of the navy, to take the Admiralty into his counsels, and he accordingly communicated his intention to that Board, with the result that many of the specimens of timber experimented on were sent from Woolwich dockyard, and the results of the trials were from time to time communicated to the Admiralty.

The different blocks of timber under trial were treenailed to the rock, and the experiments extended over a period of nearly thirty years. They clearly proved that teak, African oak, English and American oak, mahogany, beech¹⁰, ash, elm, and the different varieties of pine, were found sooner or later to become a prey¹¹ to the Limnoria. Greenheart oak was alone found to withstand their attacks, and even this timber was ultimately not entirely¹² unaffected.

The result of these valuable experiments is given in the following Table:—

157

Table showing the different kinds of Timber which were exposed to the attacks of the Limnoria terebrans at the Bell Rock in 1814, 1821, 1837, 1843, with their durabilities.
Kind of Timber.    Decay
first
observed.    Unsound
and
quite
decayed.    Quite
sound
for    Remarks.
      yrs.     mo.     yrs.     mo.     yrs.     mo.      
Greenheart,1                             19     ?0     1 Affected¹³ in one corner.
Teak-wood,                             13     ?0      
Beef-wood,                             13     ?0      
Treenail of Bullet-wood,                             ?5     ?0      
Beech, Payne’s patent pro⁹.,2     10     ?7                             2 A little holed at one end underneath¹⁴. Nearly sound 7? years after being laid down.
Teak-wood,3     ?5     ?6                              
African Oak,4     ?5     ?6                             3 Nearly sound 7? years after being laid down.
Do. do.     ?4     11     10     ?0                 4 Nearly sound 7? years after being laid down.
English Oak, kyanised,     ?4     ?7     10     ?0                  
Teak-wood,     ?4     ?7     12     ?0                  
American Oak, kyanised,5     ?4     ?3                             5 Decaying, but slowly, 5 years and 7 months after being laid down.
British Ash,     ?3     ?0     ?5     ?0                  
Scotch¹⁵ Elm,     ?3     ?0     ?5     ?0                  
Ash,     ?2     11     ?4     ?3                  
English Elm,     ?2     11     ?4     ?7                  
Plane Tree,6     ?2     11                             6 Decaying, but slowly, 5 years and 7 months after being laid down.
American Oak,     ?2     11     ?4     ?7                  
Baltic Red Pine,7     ?2     ?9     ?4     ?3                 7 A good deal decayed when first observed.
English Oak,     ?2     ?4     ?4     ?7                  
Scotch Oak,8     ?2     ?4                             8 Much decayed when first observed.
Baltic Oak,     ?2     ?4     ?4     ?3                  
Norway Fir,     ?2     ?4     ?3     ?1                  
Baltic Red Pine, kyanised,     ?2     ?4     ?4     ?7                  
Pitch Pine,     ?2     ?4     ?4     ?3                  
American Yellow Pine,     ?2     ?4     ?3     ?7                  
American Red Pine,     ?2     ?4     ?3     ?1                  
Do. do., kyanised,     ?2     ?4     ?4     ?7                  
Larch¹⁶,     ?2     ?4     ?4     ?3                  
Honduras Mahogany,9     ?2     ?1                             9 Nearly sound 3? years after being laid down. Washed away 6 months later.
Beech,     ?1     ?9     ?3     ?1                  
American Elm,     ?1     ?9     ?3     ?1                  
Treenail of Locust¹⁷,     ?5     ?0     ?3     ?0                  
British Oak,     ?1     ?6     ?5     ?0                  
American Oak,     ?1     ?6     ?5     ?0                  
Plane Tree,     ?1     ?6     ?5     ?0                  
Honduras Teak treenails,     ?1     ?6     ?5     ?0                  
Beech,     ?1     ?6     ?5     ?0                  
Scotch Fir, teak treenails,     ?1     ?6     ?3     ?0                  
Do. from Lanarkshire,     ?1     ?6     ?3     ?0                  
Do. do.     ?1     ?6     ?3     ?0                  
Do. Locust treenails,     ?1     ?6     ?3     ?0                  
Memel Fir,     ?1     ?6     ?5     ?0                  
Pitch Pine,10     ?1     ?6     ?2     ?6                 10 Going fast when first observed.
English Oak,     ?1     ?1     ?3     ?1                  
Italian Oak,     ?1     ?1     ?3     ?6                  
Dantzic Oak,     ?1     ?1     ?2     ?6                  
English Elm,     ?1     ?1     ?1     ?6                  
Canada Rock Elm,     ?1     ?1     ?1     ?6                  
Cedar¹⁸ of Lebanon,     ?1     ?1     ?2     ?6                  
Riga Fir,     ?1     ?1     ?1     ?6                  
Dantzic Fir,     ?1     ?1     ?1     ?6                  
Virginia Pine,     ?1     ?1     ?1     ?6                  
Yellow Pine,11     ?1     ?1     ?1     ?6                 11 A good deal gone 18 months after being laid down. Swept away by the sea 7 months afterwards.
Red Pine,     ?1     ?1     ?1     ?6                  
Cawdie Pine,12     ?1     ?1     ?1     ?6                 12 A good deal decayed when first observed.
Polish Larch,13     ?1     ?1     ?1     ?6                 13 Going fast when first observed.
Birch, Payne’s patent pro.,     ?0     10     ?1     10                  
American Locust treenails,     ?0     ?8     ?3     ?0                  

158 Mr. Stevenson seems to have formed an opinion that the best preservative¹⁹ against decay was charring the timber, as recommended in the following extract from a report, made in 1811, to the Trustees of Montrose Bridge:—

    “The changeableness of climate to which the northern parts of this island are subject renders edifices²⁰ of timber more liable to decay here than perhaps in any other country in Europe. But the bridge at Montrose is curiously²¹ circumstanced; for while it unavoidably exposes a great surface of timber to the action of the weather, some of the wooden piers²² are immersed twenty-two feet in the water, where they are attacked by a destructive marine worm. Some of the woodwork at the Bell Rock was infested²⁴ with the same species of animal which preys²⁵ upon the wooden pier²³ at Montrose. In some of the temporary works there, as in the beams laid for carrying the railway over the inequalities of the rock, the timber was so much wormed that some logs measuring one foot when laid down would not square to more than nine inches at the end of three years. The beams which supported the wooden house for the accommodation of the artificers while the lighthouse was erecting²⁶ escaped almost untouched, having been slightly charred²⁷, but the reporter, when inspecting the Bell Rock works this year, found that these worms are making some impression upon the ends of the supports resting on the rock where the charring could not take effect. The reporter is therefore of opinion that there is no better defence against the effects of this animal than slightly charring the timber, and he would recommend the practice at the bridge of Montrose wherever it can be applied²⁸. The operation of charring at the Bell Rock was performed by previously²⁹ scraping off the adhering matter upon the logs and laying the skin of the wood open, and tar³⁰ was applied to promote the combustion³¹. Charcoal³², besides being tasteless and inodorous,159 possesses some very curious properties in its action upon vegetable and animal substances, which may not only render it insipid³³, but even offensive to this insect. For those parts between the high-water mark and the roadway it will be enough to scrape the timber and lay it over with hot tar.”

I need hardly say that this advice would perhaps not have been given at the present day, when even creosote has been found to delay, though not to act as a perfect defence against, the ravages³⁴ of the Limnoria.10
PRESERVATION³⁵ OF IRON.

At a more recent period Mr. Stevenson experimented at the Bell Rock Lighthouse in the same way on twenty-five different kinds of malleable³⁶ iron, with the result that all of them were soon affected, and that galvanised specimens resisted oxidation from three to four years, after which the chemical action went on as quickly as in the others.

1 specimens   

n.样品( specimen的名词复数 )；范例；（化验的）抽样；某种类型的人

参考例句：

• Astronauts have brought back specimens of rock from the moon. 宇航员从月球带回了岩石标本。
• The traveler brought back some specimens of the rocks from the mountains. 那位旅行者从山上带回了一些岩石标本。 来自《简明英汉词典》

2 leach   

v.分离，过滤掉；n.过滤；过滤器

参考例句：

• Liquid water can leach soluble materials from the interface.液态水能够从界面溶解出可溶性物质。
• They believe that the humic materials are leached from decaying plant materials.他们认为腐植物料是从腐烂的植物体浸沥而来。

3 eminent   

adj.显赫的，杰出的，有名的，优良的

参考例句：

• We are expecting the arrival of an eminent scientist.我们正期待一位著名科学家的来访。
• He is an eminent citizen of China.他是一个杰出的中国公民。

4 naturalist   

n.博物学家(尤指直接观察动植物者)

参考例句：

• He was a printer by trade and naturalist by avocation.他从事印刷业，同时是个博物学爱好者。
• The naturalist told us many stories about birds.博物学家给我们讲述了许多有关鸟儿的故事。

5 marine   

adj.海的；海生的；航海的；海事的；n.水兵

参考例句：

• Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
• When the war broke out,he volunteered for the Marine Corps.战争爆发时，他自愿参加了海军陆战队。

6 systematic   

adj.有系统的，有计划的，有方法的

参考例句：

• The way he works isn't very systematic.他的工作不是很有条理。
• The teacher made a systematic work of teaching.这个教师进行系统的教学工作。

7 fully   

adv.完全地，全部地，彻底地；充分地

参考例句：

• The doctor asked me to breathe in,then to breathe out fully.医生让我先吸气，然后全部呼出。
• They soon became fully integrated into the local community.他们很快就完全融入了当地人的圈子。

8 strictly   

adv.严厉地，严格地；严密地

参考例句：

• His doctor is dieting him strictly.他的医生严格规定他的饮食。
• The guests were seated strictly in order of precedence.客人严格按照地位高低就座。

9 pro   

n.赞成，赞成的意见，赞成者

参考例句：

• The two debating teams argued the question pro and con.辩论的两组从赞成与反对两方面辩这一问题。
• Are you pro or con nuclear disarmament?你是赞成还是反对核裁军？

10 beech   

n.山毛榉；adj.山毛榉的

参考例句：

• Autumn is the time to see the beech woods in all their glory.秋天是观赏山毛榉林的最佳时期。
• Exasperated,he leaped the stream,and strode towards beech clump.他满腔恼怒，跳过小河，大踏步向毛榉林子走去。

11 prey   

n.被掠食者，牺牲者，掠食；v.捕食，掠夺，折磨

参考例句：

• Stronger animals prey on weaker ones.弱肉强食。
• The lion was hunting for its prey.狮子在寻找猎物。

12 entirely   

ad.全部地，完整地；完全地，彻底地

参考例句：

• The fire was entirely caused by their neglect of duty. 那场火灾完全是由于他们失职而引起的。
• His life was entirely given up to the educational work. 他的一生统统献给了教育工作。

13 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

14 underneath   

adj.在...下面，在...底下；adv.在下面

参考例句：

• Working underneath the car is always a messy job.在汽车底下工作是件脏活。
• She wore a coat with a dress underneath.她穿着一件大衣，里面套着一条连衣裙。

15 scotch   

n.伤口，刻痕；苏格兰威士忌酒；v.粉碎，消灭，阻止；adj.苏格兰(人)的

参考例句：

• Facts will eventually scotch these rumours.这种谣言在事实面前将不攻自破。
• Italy was full of fine views and virtually empty of Scotch whiskey.意大利多的是美景，真正缺的是苏格兰威士忌。

16 larch   

n.落叶松

参考例句：

• This pine is called the larch.这棵松树是落叶松。
• I shall be under those larch trees.我将在那些落叶松下面。

17 locust   

n.蝗虫；洋槐，刺槐

参考例句：

• A locust is a kind of destructive insect.蝗虫是一种害虫。
• This illustration shows a vertical section through the locust.本图所示为蝗虫的纵剖面。

18 cedar   

n.雪松，香柏(木)

参考例句：

• The cedar was about five feet high and very shapely.那棵雪松约有五尺高,风姿优美。
• She struck the snow from the branches of an old cedar with gray lichen.她把长有灰色地衣的老雪松树枝上的雪打了下来。

19 preservative   

n.防腐剂；防腐料；保护料；预防药

参考例句：

• New timber should be treated with a preservative.新采的圆木应进行防腐处理。
• Salt is a common food preservative.盐是一种常用的食物防腐剂。

20 edifices   

n.大建筑物( edifice的名词复数 )

参考例句：

• They complain that the monstrous edifices interfere with television reception. 他们抱怨说，那些怪物般的庞大建筑，干扰了电视接收。 来自辞典例句
• Wealthy officials and landlords built these queer edifices a thousand years ago. 有钱的官吏和地主在一千年前就修建了这种奇怪的建筑物。 来自辞典例句

21 curiously   

adv.有求知欲地；好问地；奇特地

参考例句：

• He looked curiously at the people.他好奇地看着那些人。
• He took long stealthy strides. His hands were curiously cold.他迈着悄没声息的大步。他的双手出奇地冷。

22 piers   

n.水上平台( pier的名词复数 )；（常设有娱乐场所的）突堤；柱子；墙墩

参考例句：

• Most road bridges have piers rising out of the vally. 很多公路桥的桥墩是从河谷里建造起来的。 来自辞典例句
• At these piers coasters and landing-craft would be able to discharge at all states of tide. 沿岸航行的海船和登陆艇，不论潮汐如何涨落，都能在这种码头上卸载。 来自辞典例句

23 pier   

n.码头；桥墩，桥柱；[建]窗间壁，支柱

参考例句：

• The pier of the bridge has been so badly damaged that experts worry it is unable to bear weight.这座桥的桥桩破损厉害，专家担心它已不能负重。
• The ship was making towards the pier.船正驶向码头。

24 infested   

adj.为患的，大批滋生的（常与with搭配）v.害虫、野兽大批出没于( infest的过去式和过去分词 )；遍布于

参考例句：

• The kitchen was infested with ants. 厨房里到处是蚂蚁。
• The apartments were infested with rats and roaches. 公寓里面到处都是老鼠和蟑螂。

25 preys   

v.掠食( prey的第三人称单数 )；掠食；折磨；（人）靠欺诈为生

参考例句：

• His misfortune preys upon his mind. 他的不幸使她心中苦恼。 来自辞典例句
• The owl preys on mice. 猫头鹰捕食老鼠。 来自辞典例句

26 erecting   

v.使直立，竖起( erect的现在分词 )；建立

参考例句：

• Nations can restrict their foreign trade by erecting barriers to exports as well as imports. 象设置进口壁垒那样，各国可以通过设置出口壁垒来限制对外贸易。 来自辞典例句
• Could you tell me the specific lift-slab procedure for erecting buildings? 能否告之用升板法安装楼房的具体程序？ 来自互联网

27 charred   

v.把…烧成炭( char的过去式)；烧焦

参考例句：

• the charred remains of a burnt-out car 被烧焦的轿车残骸
• The intensity of the explosion is recorded on the charred tree trunks. 那些烧焦的树干表明爆炸的强烈。 来自《简明英汉词典》

28 applied   

adj.应用的；v.应用，适用

参考例句：

• She plans to take a course in applied linguistics.她打算学习应用语言学课程。
• This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。

29 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。

30 tar   

n.柏油，焦油；vt.涂或浇柏油/焦油于

参考例句：

• The roof was covered with tar.屋顶涂抹了一层沥青。
• We use tar to make roads.我们用沥青铺路。

31 combustion   

n.燃烧；氧化；骚动

参考例句：

• We might be tempted to think of combustion.我们也许会联想到氧化。
• The smoke formed by their combustion is negligible.由它燃烧所生成的烟是可忽略的。

32 charcoal   

n.炭，木炭，生物炭

参考例句：

• We need to get some more charcoal for the barbecue.我们烧烤需要更多的碳。
• Charcoal is used to filter water.木炭是用来过滤水的。

33 insipid   

adj.无味的，枯燥乏味的，单调的

参考例句：

• The food was rather insipid and needed gingering up.这食物缺少味道，需要加点作料。
• She said she was a good cook,but the food she cooked is insipid.她说她是个好厨师，但她做的食物却是无味道的。

34 ravages   

劫掠后的残迹，破坏的结果，毁坏后的残迹

参考例句：

• the ravages of war 战争造成的灾难
• It is hard for anyone to escape from the ravages of time. 任何人都很难逃避时间的摧残。

35 preservation   

n.保护，维护，保存，保留，保持

参考例句：

• The police are responsible for the preservation of law and order.警察负责维持法律与秩序。
• The picture is in an excellent state of preservation.这幅画保存得极为完好。

36 malleable   

adj.(金属)可锻的;有延展性的；(性格)可训练的

参考例句：

• Silver is the most malleable of all metals.银是延展性最好的金属。
• Scientists are finding that the adult human brain is far more malleable than they once thought.科学家发现成人大脑的可塑性远超过他们之前认识到的。