Ruthenium in the tetrad condition gives a dark violet coloration in solution with potassium thiocyanate which distinguishes it from other metals of this group. Sulphuretted hydrogen gives first a blue coloration and then a brown precipitate insoluble in ammon ium sulphide. Ruthenium or its compounds fused with caustic potash and nitre give a green mass which on extraction gives an orange solution of lcRua, and this on acidification gives a dark brown or black precipitate. Except for ruthenium red, no practical use for ruthenium or any of its compounds has been found. If present in anything but the smallest quantity, it has a deleterious effect upon the properties of the other platinum metals, and hence these should be freed from ruthenium as far as possible. A practi cal use for ruthenium or some of its compounds is very desirable as large stocks of the metal have accumulated in the course of years and these are at present useless. (F. E. M.) RUTHERFORD, ERNEST RUTHERFORD, 1ST BARON (1871-1937), British physicist, was born at Nelson, New Zealand, on Aug. 3o, 1871, and studied at the University of New Zealand.
After a period of research at Cambridge, he became in 1898 Mac donald professor of physics in McGill university, Montreal; in 1907, Langworthy professor of physics at Manchester university; and in 1919 Cavendish professor of experimental physics in the University of Cambridge, accepting, in addition, in 1920, the pro fessorship of physics at the Royal Institution, London. His bril liant researches established the existence and nature of radio active transformations, the electrical structure of matter, and the nuclear nature of the atom. He was elected F.R.S. in 1903, and was knighted in 1914. Many British and foreign degrees and honours were bestowed upon him. He was awarded the Nobel Prize for chemistry in 1908 and was president of the British Asso ciation, 1923, and of the Royal Society, 1925-30. He was created a baron in 1931 and died in Cambridge, England, Oct. 19, 1937. His works include Radio-activity (1904) , Radioactive Transforma tions (1906) ; Radioactive Substances and their Radiations (1912), and numerous papers in The Transactions of the Royal Society, The Philosophical Magazine, etc.