Before Discovery

Before Discovery

384BCE-1675ACE

Aristotle believed there were only four elements that made up all matter on earth. These elements were earth, air, wind and fire. For thousands of years this was accepted as fact. In the seventeenth century scientists such as Robert Boyle started to question this theory. They put forward the belief that there were many different elements made up of particles called atoms. At the atomic theory gained credence, scientists began looking at the common substances around them to find which were elements and which were compounds or salts of two or more of these elements.

Examination of spectrographs from minerals has revealed the presence of many elements that were previously unknown. Many elements, such as samarium and thallium, were found spectroscopically before they could be isolated and identified.

The element helium was also discovered spectrographically but this spectrograph was not from an earth mineral..