550 



SCIENCE 



[N. S. Vol. XXVIII. No. 721 



field by many distinguished chemists, we 

 note in particular TJrbain's recent separa- 

 tion of ytterbium into lutecium and neoyt- 

 terbium, a separation pi'eviously indicated 

 by Welsbach, and the still more recent 

 work of James upon the bromate separa- 

 tion of yttrium earths, and the arrange- 

 ment of the rare eai-th separation methods 

 into a systematic scheme of analysis.* 

 This latter piece of work certainly reflects 

 great credit upon this painstaking inves- 

 tigator, and I will venture the prediction 

 that if we keep our eyes upon Urbain and 

 James we shall be rewarded by something 

 more than mere spectacular spectroscopic 

 speculations. Marc in a recent paper 

 upon the "Development of our Knowledge 

 of the Rare Earths and their Significance" 

 calls attention in closing to a reference by 

 Crookes to the rare earth minerals as a 

 cosmic rummage chamber, and significantly 

 adds that often the most important facts 

 concerning the history of a family are to 

 be found in rummage chambers. 



Since thorium and zirconium are in- 

 cluded by Bohm among the rare earths and 

 are closely associated with them, these ele- 

 ments will be taken up at this point. The 

 mention of thorium in this connection is 

 certainly most appropriate, for it can not 

 be questioned that the use of thorium 

 nitrate in the preparation of the mantles 

 used in incandescent gas lighting, and the 

 development of this great industry have 

 given a mighty impetus to the study of the 

 rare earths. 



A few figures will give us some idea of 

 the growing importance of thorium and its 

 chief mineral source, monazite. In 1902 

 the production of monazite sand in the 

 United States and Brazil amounted to 

 3,500,000 pounds, with a value of $324,- 

 000; while the last report, that of 1906, 

 shows a production of 10,450,000 pounds, 

 with a value of $630,000— an increase in 



'Jour. Amer. Cliem. Soc, XXX., 979, June, 1908. 



value of almost 100 per cent. In the 

 United States alone, and almost exclusively 

 from Henderson County, N. C, the value 

 of monazite sand produced has increased 

 from about $65,000 in 1902, to about $153,- 

 000 in 1906. Of interest and importance 

 in this connection is the new mineral 

 thorianite discovered in Ceylon in 1904. 

 It carries from 70 per cent, to 80 per cent, 

 of thorium oxide, and the report of 1905 

 shows an export of about 18,000 pounds, 

 valued at about $24,000. 



Helpful to the student of thorium are 

 the works of Bohm and Schilling already 

 mentioned, as well as the "Index to the 

 Literature of Thorium" by Jouet, pub- 

 lished by the Smithsonian Institution in 

 1903. 



In considering zirconium we would note 

 in particular the work of Rosenheim on 

 the zirconyl salts and the investigations of 

 Wedekind, who finds a practical method 

 for the production of zirconium carbide, 

 a compound resistant to air, water, and 

 hydrochloric acid, and said to be an excel- 

 lent conductor of electricity. Ninety 

 parts of this carbide with ten parts of the 

 metal ruthenium have been made by Sand- 

 ers into filaments for use in the zirconium 

 lamp. A mixture consisting of eighty-five 

 parts of zirconium oxide and fifteen parts 

 of yttrium earth oxides of the higher 

 atomic weights is used in the manufacture 

 of the Nernst glowers. The production 

 of zircon in this country, much of it ob- 

 tained as a by-product from monazite con- 

 centrates, has not been large; as reported 

 in 1906 it amounted to 1,100 pounds, 

 valued at $248. 



In connection with the subject of rare 

 earths it is perhaps of interest to refer to 

 the growing use of eerie and cerous com- 

 pounds as oxidizing and reducing agents; 

 to Barbieri's statement in regard to cer- 

 ium salts as catalytic agents, their behav- 

 ior being similar to that of manganese 



