本图像(或本页面/分类中的所有图像)非常小，模糊，曝光不足/过度，或者可能没有充分展示图片的主题。如果有高质量的图片可用，请替换本图像，否则请寻找一个(在自由版权下) 可以提换的版本。 请参看Category:Image cleanup templates中使用了本模板的图像，并帮助清理。 进一步的帮助信息请参看Commons:Media for cleanup#Low quality pictures。

本檔案是由Maksim從en.wikipedia轉移到維基共享資源。

This is a scan of a Pickett pocket slide rule, done by me, Benjamin Crowell, in 2005. The slide rule does not have a copyright notice on it, and works published in the U.S. without a copyright notice before 1977 are in the public domain. I therefore think the slide rule itself is in the public domain under U.S. law. I'm making my scan available under the GFDL license.

已授权您依据自由软件基金会发行的无固定段落及封面封底文字（Invariant Sections, Front-Cover Texts, and Back-Cover Texts）的GNU自由文件许可协议1.2版的条款，复制、传播和／或修改本文件。该协议的副本请见“GNU Free Documentation License”。

仅1.2版http://www.gnu.org/licenses/old-licenses/fdl-1.2.htmlGFDL 1.2GNU Free Documentation License 1.2truetrue

原始上传日志

Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version.

Click on date to download the file or see the image uploaded on that date.

• (del) (cur) 19:33, 23 April 2005 . . en:User:Bcrowell Bcrowell ( en:User_talk:Bcrowell Talk) . . 558x152 (20510 bytes) (This is a scan of a Pickett pocket slide rule, done by me, Benjamin Crowell, in 2005. The slide rule does not have a copyright notice on it, and works published in the U.S. without a copyright notice before 1977 are in the public domain. I therefore think)
• (del) (rev) 19:24, 23 April 2005 . . en:User:Bcrowell Bcrowell ( en:User_talk:Bcrowell Talk) . . 634x174 (25206 bytes) (This is a scan of a Pickett pocket slide rule, done by Benjamin Crowell in 2005. The slide rule does not have a copyright notice on it, and works published in the U.S. without a copyright notice before 1977 are in the public domain. I therefore think the )
• (del) (rev) 19:18, 23 April 2005 . . en:User:Bcrowell Bcrowell ( en:User_talk:Bcrowell Talk) . . 652x203 (27548 bytes) (This is a scan of a Pickett pocket slide rule, done by Benjamin Crowell in 2005. The slide rule does not have a copyright notice on it, and works published in the U.S. without a copyright notice before 1977 are in the public domain. I therefore think the )