April - 5 years ago; 20 years ago; 65 years ago; 85 years ago; 115 years ago; 230 years ago

5 years ago
Death of biochemist Heinz Fraenkel-Conrat. He discovered that genetic information for viral reproduction is in a virus’s nucleic acid core. Cited as the first man to take apart, separate and put back together a live virus.

20 years ago
US President Ronald Reagan called for an international ban on chemical weapons.

65 years ago
Ernest Volwiler and Donalee Tabern patented sodium pentothal, a general anaesthetic that is injected straight into the blood causing unconsciousness with no adverse effects. It is now one of modern medicine’s most important agents.

85 years ago
Death of Sir William Crookes, who discovered thallium and the phenomena behind the Crookes radiometer: vanes that are black on one side and polished on the other that rotate when exposed to radiant energy.

115 years ago
Death of French chemist Michel-Eugene Chevreul, famed for his work on the chemistry of fats that revolutionised the soap and candle making industries. Shortly after his 100th birthday he began to study the effects of ageing on the human body.

230 years ago
Birth of Jean-Baptiste Biot, co-discoverer of the Biot-Savart law relating the intensity of a magnetic field set up by current flow to the distance from the wire. He won the Rumford Medal of the Royal Society for his work on light polarisation in chemical solutions.

Sallie Robins