April - 35 years ago; 95 years ago; 105 years ago; 110 years ago; 160 years ago; 185 years ago

35 years ago 

UK crystallographer Kathleen Lonsdale died. She developed x-ray techniques for studying crystal structures and revealed the bond lengths and angles of benzene. 

95 years ago 

Melvin Calvin was born in Minnesota, US. He received the 1961 Nobel prize for chemistry for his research on the mechanism by which carbon dioxide is assimilated in plants in the night (the Calvin cycle).  

105 years ago 

Fran?ois-Marie Raoult died. He formulated a law on solutions (Raoult’s law) that made it possible to determine the molecular weights of dissolved substances. 

110 years ago 

US chemist Wallace Hume Carothers was born in Iowa, US. He developed nylon, a synthetic analogue of silk, which revolutionised the stocking industry. He also developed the synthetic rubber neoprene. 

160 years ago 

Raoul Pierre Pictet was born in Switzerland. Known as a pioneer of cryogenics, he studied the production of extremely low temperatures, using cascade methods to form large quantities of liquefied gases.  

185 years ago 

German chemist Franz Karl Achard died. He invented a process for the large-scale extraction of sucrose from beets. In 1801 he opened the first sugar beet factory in Silesia (Poland).