<tt id="6hsgl"><pre id="6hsgl"><pre id="6hsgl"></pre></pre></tt>
          <nav id="6hsgl"><th id="6hsgl"></th></nav>
          国产免费网站看v片元遮挡,一亚洲一区二区中文字幕,波多野结衣一区二区免费视频,天天色综网,久久综合给合久久狠狠狠,男人的天堂av一二三区,午夜福利看片在线观看,亚洲中文字幕在线无码一区二区
          您現在的位置: Language Tips> Easy English> Odd Question  
           





           
          Who invented the pencil?
          [ 2005-04-25 07:30 ]
             
            Pencil
             
            Who invented the pencil?
          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 pulverizedgraphitebase 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 familyfollowed 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, 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 flavors, each designed for a specific use, and may be purchased in over 72 colors. "Black pencils," 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 out door 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.

           

          note:

           

           

          graphite :石墨

           


          follow suit: 效仿

           
           
          相關文章 Related Stories
           
           
           

          本頻道最新推薦

               
            為什么下雪時天氣暖
            You are the smartest fish I've ever seen!
            Dog burger
            為什么老了脾氣好
            飛蛾為什么撲火

          論壇熱貼

               
            開個題目大家扯:hotel & restaurant
            追求某人
            請教工商年檢如何翻譯
            How to translate “中國老字號”into English?
            "港股直通車"怎么翻譯?
            兩免一補怎么說?




          主站蜘蛛池模板: 亚洲天堂一区二区久久| 人妻熟妇乱又伦精品无码专区| 7777久久亚洲中文字幕蜜桃 | 国产精品成人一区二区三| 2020精品自拍视频曝光| 婷婷99视频精品全部在线观看| 浪潮av色综合久久天堂| 国产精品一区二区三区黄色| 亚洲尤码不卡av麻豆| 欧美巨大极度另类| 丁香婷婷在线视频| 国产日韩欧美亚洲精品95 | 亚洲高清日韩heyzo| 夜夜添无码一区二区三区| 欧美成人免费全部观看国产| 久久人妻无码一区二区三区av| 午夜福利理论片高清在线| 日韩精品中文字幕国产一| 国产一区二区不卡91| 成年视频人免费网站动漫在线 | 国产乱弄免费视频观看| 久久精品夜夜夜夜夜久久| 手机在线观看av片| 国产精品伊人久久综合网| 人妻少妇精品系列一区二区| av一区二区中文字幕| 成人拍拍拍无遮挡免费视频 | 少妇伦子伦精品无吗| 免费国产一区二区不卡| 伦伦影院精品一区| 综合色天天久久| 亚洲一区二区三区无码久久| 高清中文字幕国产精品| 最新国产精品亚洲| 国产成人一区二区三区免费| 成人免费视频一区二区| 无码熟妇人妻av影音先锋| 国产精品资源在线观看网站| 亚洲国产精品第一区二区| 青青青视频91在线 | 一区二区在线观看成人午夜|