Un livre de Becquerel sur les effets de la lumi re sur les corps, explorant des ph nom nes tels que la fluorescence et la polarisation de la lumi re. Il aborde galement des questions telles que la nature des rayons cathodiques et la th orie de l' ther. This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United...