The Musée McCord has a Flickr account with some fantastic images in the public domain, including these 1860s vintage shots of children posing with their toys. I have a theory about why people always look so serious in old photos. When it came to posing for pictures, the camera took over from the oil painting. No one can hold a smile very long and you know how long it took to pose for paintings, which were considered a serious endeavor. So when the camera came along, it took people time to think about it differently. Just as early TV was nothing more than radio programs with cameras capturing them.