ON THE MEASUREMENT OF PHYSICAL SENSATIONS AND ON THE LAW WHICH LINKS THE INTENSITY OF THESE SENSATIONS TO THE INTENSITY OF THE SOURCE - REPORT ON PSYCHOPHYSICAL STUDY - THEORETICAL AND EXPERIMENTAL RESEARCH ONTHE MEASUREMENT OF SENSATIONS, PARTICULARLY SENSATIONS OF LIGHT AND OF FATIGUE

Two papers published in 1872 by the Belgian physicist Plateau are here translated into English. The first paper contains the earliest publis hed suggestion that the relation between physical stimulus magnitude a nd the strength of the internal sensation evoked is a power law and ha s been much cited for this reason. It also describes the earliest expe riment to be performed, though not the first to be reported, on the su bject of the psychophysical law. The performance of that experiment an tedated Fechner's Elemente ner Psychophysik by about 20 years. The sec ond paper summarises a memoir in which a colleague, Delboeuf, reports his more extensive experiments on the subject and commends that memoir to the Belgian Royal Academy. In this second paper Plateau concludes that he was mistaken in supposing the psychophysical law to be a power relation.