Under these circumstances it would appear natural to have just as much interest and energy and incessant thought devoted to this very great and significant industry as to any branch of manufacturing. But the opposite is true. Armies of engineers and of scientifically trained workers have put half a century of scholarly research and experimental investigation into the perfecting of the physical and chemical industries. The most thorough study is devoted to the raw material and to the machines, to the functions of the workingman and to everything which improves the mechanical output. In striking contrast to this, the gigantic industry of advertising is to-day still controlled essentially by an amateurish impressionism, by a so-called commonsense, which is nothing but the uncritical following of a well-worn path. Surely there is an abundance of clever advertisement writers at work, and great establishments make some careful tests before they throw their millions of circulars before the public. Yet even their so-called tests have in no way scientific character. They are simply based on watching the success in practical life, and the success is gained by instinct. Commonsense tells even the most superficial advertiser that a large announcement will pay more than a small one, an advertisement in a paper with a large circulation more than in a paper with a few subscribers, one with a humorous or emotional or exciting text more than one with a tiresome and stale text. He also knows that the cover page in a magazine is worth more than the inner pages, that a picture draws attention, that a repeated insertion helps better than a lonely one. Yet even a score of such rules would not remove the scheme of advertising from the commonplaces of the trade. They still would not show any trace of the fact that the methods of exact measurement and of laboratory research can be applied to such problems of human society. Advertising is an appeal to the attention, to the memory, to the feeling, to the impulses of the reader. Every printed line of advertisement is thus a lever which is constructed to put some mental mechanism in motion. The science of the mental machinery is psychology, which works on principles with the exact methods of the experiment. It seems unprogressive, indeed, if just this one industry neglects the help which experimental science may furnish. A few slight beginnings, to be sure, have been made, but not by the men of affairs, whose practical interests are involved. They have been made by psychologists who in these days of carrying psychology into practical life have pushed the laboratory method into the field of advertising.