Illustration from 1911 Encyclopædia Britannica, article Bridges.

Original text: Let a uniform train weighing w per ft. run advance over a girder of span 2c, from the left abutment. When it covers the girder to a distance x from the centre (fig. 41) the total load is w(c+x);

This image comes from the 13th edition of the Encyclopædia Britannica or earlier. The copyrights for that book have expired in the United States because the book was first published in the US with the publication occurring before January 1, 1929. As such, this image is in the public domain in the United States.

This image comes from the Project Gutenberg archives. This is an image that has come from a book or document for which the American copyright has expired and this image is in the public domain in the United States and possibly other countries. Note: Not all works on Project Gutenberg are in the public domain. Some public domain works may have trademark restrictions where all references to the Project Gutenberg must be removed unless the following text is prominently displayed according to The Full Project Gutenberg License in Legalese (normative): This eBook is for the use of anyone anywhere at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this eBook or online at www.gutenberg.net.