William Crookes:
Crookes was an English chemist who discovered the element thallium.
Birth:
June 17, 1834 in London, England
Death:
April 4, 1919 in London, England
Claim to Fame:
Crookes was an English chemist who discovered the element thallium. He also discovered negative electrical cathodes in low pressure emit 'cathode rays' or a stream of fast moving electrons. The Crookes radiometer, sold in many museum gift shops and novelty stores was an accidental invention while trying to weigh out samples in a partially evacuated scale. He noticed the scale would move when struck by sunlight. He built the device to investigate this phenomenon.