http://www.quaker.org/wmpenn.htmlIt is a boring site
Click on the link to your right for more info.
See the web links to the left for information.
Try the price guide (amazon.com) or soupdiner.com.
In answer to the question: Where can you find information on a Hopkins and Allen Rifle? You can find most any gun list'ed on this web page,and I'am sure that you can find what you are looking for...