I just stumbled upon a great website. The first link I am sharing is for a page called "Singer Through the Ages". There is a wealth of information about antique sewing machines on this man's website. Be sure to browse and click around.
http://www.sewalot.com/singer_through_the_ages.htm
This next link is to his main index. Tons of info about all different types of antique machines.
http://www.sewalot.com/sewalot_index.htm
Enjoy!