APPENDIX 475 



SIR WILLIAM CROOKES, O.M., Foreign Secretary (1908-1912), 

 and President of the Eoyal Society (1913-1915). He has received 

 the Royal, Davy, and Copley Medals of the Eoyal Society. 



Sir William Crookes received his scientific education in the 

 Royal College of Chemistry, London, under Hofmann's professor- 

 ship. 



In 1851 he published his first paper, being then in his nineteenth 

 year. By the use of the then new method of spectrum analysis he 

 discovered in 1861 the metal thallium, which presents curious 

 chemical features intermediate between those of potassium and 

 lead. As a result of the study of certain peculiarities of attenuated 

 gases he devised in 1875 the radiometer. Pursuing his investigation 

 on the electric discharge he was led to announce a fourth state of 

 matter (1879), and described the phenomena exhibited by " radiant 

 matter " in 1881. These early investigations were the means of 

 attracting the attention of other investigators to the subject, and 

 provided a starting-point for the work of the Cambridge school 

 which under Sir J. J. Thomson has in recent years achieved such 

 wonderful discoveries. Crookes' views on the nature and origin of 

 the elements have attracted much attention, and a condensed account 

 of them is given in the text. 



For the purpose of collecting information concerning the origin 

 of the diamond he paid two visits to Kimberley, the second in 1905, 

 when over seventy years of age. 



Sir William Crookes was President of the Chemical Society in 

 1888 and 1889. He has also been President of the British Associa- 

 tion and of the Institution of Electrical Engineers. He has received 

 many honours, including Honorary Membership of the R. Accademia 

 dei Lincei (Rome), and Corresponding Membership of the Institute 

 of France (Academy of Sciences). 



MADAME MARIE CURIE, nee Marie Sklodowska, was born at 

 Warsaw in 1867, the daughter of Professor Sklodowski. She re- 

 ceived her education first at the Lycee in her native city, afterward 

 at the Sorbonne in Paris, where she first graduated as Licenciee 

 es Sciences Physiques, Licenciee es Sciences Mathematiques, and 

 ultimately as Docteur es Sciences, on the publication of her thesis 

 on Radio-active Substances. A full translation of this thesis was 

 published in the Chemical Neivs in 1903. 



Marie Sklodowska married Professor Pierre Curie and worked 

 with him on the radioactive properties of minerals. Madame Curie 

 succeeded, after a protracted research, in separating from pitch- 

 blende salts of the element which has ever since been known as 

 radium. She also determined its atomic weight and fixed its position 

 among the elements. 



