i88 



POPULAR SCIENCE MONTHLY. 



THORIUM, CAROLINIUM AND 

 BERZELIUM. 



Ix a paper entitled ' Thorium, Caro- 

 linium, Berzelium,' presented at the 

 Chemists' Club, New York, the evening 

 of April 8, by Dr. Charles Baskerville, 

 professor of chemistry at the Univer- 

 sity of North Carolina, the following 

 interesting and important facts were 

 brought out. As the result of a num- 

 ber of years' study of the element 

 thorium, Dr. Baskerville has succeeded 

 in extracting from it two novel chem- 

 ical elements. The work indicated an 

 agreement with the conclusions of 

 Hofmann and Zerban in opposition to 

 those of Schmidt, Curie and Ruther- 

 ford, namely, that thorium is a pri- 

 mary radio-active body. Although no 

 thorium preparations had yet been pre- 

 pared absolutely free from any activ- 

 ity, numerous reasons were given which 

 pointed toward the correctness of the 

 conclusion that thorium is not a pri- 

 mary radio-active element. An ex- 

 tremely interesting observation touch- 

 ing this may be noted, namely, a prep- 

 aration was obtained from a large 

 amount of the wash waters used in the I 

 manufacture of the Welsbach mantles 

 which was very much more radio-ac- 

 tive than the original thorium and yet 

 showed no thorium by chemical 

 methods, and the merest trace was 

 found in the spectrum made with a 

 large Rowland grating. Whether it be 

 primarily radio-active or not, the 

 speaker maintained would not interfere 

 with the other conclusions obtained 

 from the investigations of himself and 

 a number of his students. 



Pure thorium was tractioned by 

 phenyl hydrazine and the fraction- <>l> 

 tained varied in their atomic weights 

 from 214 to 252, the original thorium 

 showing 232. G. That method was 

 abandoned as time-robbing, and an 

 effort was made to separate the con- 

 stituents by fractional distillation of 

 the chlorides as they were made by 

 passing chlorine over a mixture of 

 pure carbon and thorium dioxide. 

 Very elaborate apparatus was devised 



I for this purpose, the mixture being 

 placed within a carbon boat and the 

 distillation carried out within quartz 

 tubes. A white vapor was given off at 

 a comparatively low temperature which 

 1 condensed in the cooler portion of the 

 tube and was readily collected by solu- 

 tion in alcohol. The thorium was dis- 

 tilled away from the boat and collected 

 as fern-like crystals of the tetra- 

 chloride within the quartz tube. A 

 ; residue remained in the boat. These 

 three materials were more or less puri- 

 fied and atomic weight determinations 

 made of them. That which remained 

 : in the boat after different methods of 

 purification showed an atomic weight 

 of 255.6. Its oxide gave a specific 

 gravity of 11.26, the original thorium 

 having an atomic weight of 232.6 and 

 | specific gravity of 10.5. The original 

 thorium oxide was pure white, whereas 

 this residue possessed a pinkish tinge. 

 This is the carolinium of the new ele- 

 ment reported by Dr. Baskerville in 

 1900. The volatile bodv gave an 

 atomic weight of 213, assuming its 

 quadrivalence. The oxide gave a 

 specific gravity of 8.44. It possesses 

 a slight green color. As Berzelius first 

 noted this ' Meisserdampf,' stating that 

 it was not thorium, the author named 

 the element berzelium after the fa- 

 mous Swedish chemist who discovered 

 thorium. The new thorium gives a 

 white oxide and shows an atomic 

 weight of 220. The specific gravity 

 of this oxide is 9.2. Carolinium oxide 

 [ is soluble in hydrochloric acid. 

 Neither of the other oxides, nor the 

 original thorium oxide, is soluble in 

 this acid. All the oxides show radio- 

 activity. Several chemical differences 

 were also noted. The speaker care- 

 fully stated that the materials were 

 not yet in the state of purity that was 

 desired. He stated that none of these 

 substances give absorption spectra. 

 Some slight differences had been noted 

 in the arc spectra, but no definite con- 

 clusions could be drawn. Samples of 

 the materials had been sent to Sir 

 William Crookes, by request, who is 



