The Loss of the "Four Elements"

The disappearance of the traditional world of the ‘four elements’ was revolutionary. It was as radical in the world of chemistry as Copernicus’s proof that the earth was not the centre of the solar system; or (some said) as Robespierre’s claim that the people, not the king, embodied sovereignty. Moreover, it was counter-intuitive: it went against common sense and common appearances. Surely water and air were primary, simple elements? Not at all: chemical experiment and scientific inst...

 Newton's Experiment Proving White Contains All Colors

Newton wasn't the first person to make a rainbow with a prism. Other people had already got the same result. But many of them thought the prism somehow 'coloured' the white light, like adding a dye. Newton's idea was quite different. He thought that white light was a mixture of all the colours, and the prism was just separating them from each other. He was right, and he proved it with a pair of neat experiments. First, he took his prism, as before, and stuck a narrow slit in the way of the co...