What new developments in retail sales occurred in the late nineteenth century

One new development was the rise of advertising. Manufacturers realized that they could advertise their products and stimulate the demand and make people want to buy and own their products, even though in reality they might not purchase them ever without this. They started creating the consensus of what was desirable and what people had to have.

I believe the answer is: Chain stores, mail order catalogs

Chain stores were made so a company could have broader reach to more consumers which are spread in different geographic locations. Mail order catalogs is a form of purchase that can be done through telephone. This is made in otder to target the consumers who do not want to waste time going to stores.