Start with encyclopedia such as the Britannica Online. From the library website, select the "Research by Subject" tab and chose "Reference."
Also, you can check the library catalog for the book Men of Achievement. It's an e-resource that includes an him. In this case, there are no books just about him, but you could always try to "back out" a level and search for something such as an encyclopedia of inventors see if he is in one. A search for "inventors" and a limit to e-books turned up a book called "Men of Achievement" which has some information on Thomas Blanchard. I limited to e-books because I wanted to be able to scan the book immediately on-line without having to physically go find a paper copy that might not have Blanchard in it.