Early photographs took a long time to make and people needed to stand and pose. So people are just tired, especially children, and appear to be sad in the photo. Here are a few examples of such photographs of the Victorian era.
German engineer Otto Lilienthal, "airman's" philosophy was to first get up in the air, fly around with gliders, and obtain the "feel" of an airplane before putting an engine on the vehicle. Otto Lilienthal of Germany was a brilliant contributor to the conquest of the air and made nearly 2,000 successful glider flights, from 1891 to 1896, in sixteen seperate glider types. wem