Sir+William+Crookes+dannymarshall+b5


 * 1) Crookes discovered a previously unknown element with a bright green emission line in its spectrum and named the element [|**thallium**]
 * 2) Crookes also identified the first known sample of [|**helium**], in 1895.
 * 3) He was the inventor of the [|**Crookes radiometer**]**,** which today is made and sold as a novelty item
 * 4) He also developed the [|Crookes tubes], investigating [|canal rays]
 * 5) He also devised one of the first instruments for the study of nuclear radioactivity, the [|spinthariscope].