Thallium and Helium

Thallium
The book The Pale Horse, may have been the inspiration for many fatal poisonings by a mysterious element. Thallium was discovered by William Crookes in 1861, he named the element after the Greek word for the green shots on plants. At the same time Claude-Auguste Lamy also isolated thallium and in 1962 brought it to the International Exhibition, where Crookes was also showing isolated thallium. Lamy won exhibition prize and denounced Crookes discovery as nothing more then impure sulphide. Crookes later got a redress from the exhibition and gained Royal Society membership. The Pale Horse popularized thallium, for good and bad. There was a significant upcroping in thallium poisoning cases, but was also the name of a fragrance line.
Helium 
 The discovery of helium was accidental , like many other great scientific discoveries. It was an astronomer, Pierre Janssen, who while observing a solar eclipse noticed red and blue lines in the crona of the sun. Years later Norman Lockyer observed similar events and named the element helium after the Greek word for sun. In 1895 William Ramsay collected the first sample of helium and sent it to Lockyer to vindicate him.