日批在线视频_内射毛片内射国产夫妻_亚洲三级小视频_在线观看亚洲大片短视频_女性向h片资源在线观看_亚洲最大网

您現在的位置: > Language Tips > Easy English > Odd Question  
 





 
Who invented the pencil?
[ 2006-07-14 10:48 ]

鉛筆是大家從小用到大的東西。不知道你用鉛筆的時候有沒有想過它到底是怎么來的。想了解一下鉛筆是誰發明的和怎么制作的嗎?趕快看看下面這篇文章吧!

Pencil, a derivative of the Latin word pencillus for "little tail," originally described a small, fine, pointed brush.

N. J. Conte, in 1795, successfully produced pencils, after the later famed Faber family of Nuremberg, Germany, failed to do so, by using a pulverized graphite base to create a substandard, crude prototype of a pencil. Conte's method, the basic recipe used by all pencil manufacturers today, differed from the failed Faber fiasco, as he ground graphite, mixed it with certain types of clay, pressed the "dough" into sticks, and finished them in a kiln. The Faber family followed suit, and achieved the fame and fortune that previously eluded it.

The recipe used by modern pencil manufacturers, calls for dried, ground graphite, a form of carbon, mixed with clay and water in varying proportions. Pencils made with more clay produce a harder pencil, and, conversely, pencils made with more graphite produce a softer pencil. In either case, the ingredients are mixed until they reach a doughy consistency, and then pass through a forming press, which presses the dough into a pencil thin, smooth, glossy rope. After workers straighten the rope they cut it into the desired lengths, and bake them in industrial ovens.

While the mixture is prepared and baked, workers prepare the casing that will house the lead. They shape the wooden casings, made from either red cedar or pine, into halves, and carve grooves in them to encase the graphite-based leads. The workers then carefully insert the finished leads into the grooves, glue the two wooden halves together, run the resulting slats through a saw that cuts them into single pencils, and finish them with a shaping machine that smoothes the pencils' surfaces.

Modern pencils come in over 350 varieties; each designed for a specific use, and may be purchased in over 72 colors. Black pencils, or graphite-based pencils, come in 19 degrees of hardness and of intensity. Specialty pencil leads are crafted to write on surfaces such as cloth, cellophane, plastics, and movie film. Architects, engineers, and those doing outdoor construction work primarily purchase these specialty leads, as they possess non-fade, weatherproof qualities. The versatility of Conte's brainchild, the pencil, makes it the essential, indispensable tool of these trades.

pulverize: 研磨成粉

graphite: 石墨

kiln: 窯,干燥爐

doughy: 面團似的

(英語點津 Annabel 編輯)

 
 

 

 

 
 

48小時內最熱門

     

本頻道最新推薦

     
  Why are moths attracted to light?
  Pamplola Bull-running Fiesta(西班牙奔牛節)
  Deaf-blind awareness week
  Hide-and-seek
  July 11






主站蜘蛛池模板: 在线免费观看不卡av | 日本亚洲国产 | 亚洲色图国产精品 | 成人a v视频 | 国产少妇在线观看 | 小萝莉末成年一区二区 | 久射久| 久草最新视频 | 中文一区二区在线观看 | 五月天综合 | 性欧美精品 | 午夜精品久久久久久久久久久久 | 国产日产精品一区二区三区 | 美日韩成人 | 粉嫩欧美一区二区三区 | 成人在线三级 | 亚洲少妇一区二区三区 | 男男做性免费视频网 | 性天堂av | 中文字幕在线观看精品 | 午夜视频在线观看视频 | 亚洲天堂国产 | 99精品欧美一区二区三区综合在线 | 欧美日韩中文字幕在线 | 中文字幕在线观看你懂的 | 亚洲一级黄色录像 | 黄色网址av | 免费网站黄色 | 国产精品国产一区二区三区四区 | 日韩在线一区二区 | 亚洲精品aaaa | 日韩av高清| 日韩精品一二三四区 | 天天视频色 | 中文天堂在线观看 | 综合色婷婷一区二区亚洲欧美国产 | 大小姐av | 麻生希在线播放 | 精品久久在线 | 午夜久久久久久久久久影院 | 王语嫣跪趴高撅翘臀含白浆 |