Neon lamps are fun to play with. These old-school indicators were once heavily utilized in many types of equipment for indication purposes but now seem largely relegated to mains voltage indication ...

IN view of the recent letters from Prof. Joly and Sir Oliver Lodge under the above heading, I may be allowed to point out that such a theory of colour vision was advanced by me in a lecture delivered ...

II. TO continue our study of visible light, that is, undulations ex tending from red to violet in the spectrum (which I am going to show you presently), I would first point out on this chart that in ...