138 REPORTS ON INVESTIGATIONS AND PROJECTS. 



hour had lost more platinum than the other counterpoised crucible. 

 Although the heating was repeated for a great number of times, 

 it was impossible to obtain a constant weight. Likewise, if the 

 crucibles were transposed the result was not changed. For these 

 reasons further heating was considered to be unnecessary. The differ- 

 ence in the loss of weight was of a constant value and could there- 

 fore be calculated for a certain period of heating. 



After this experience it was tried whether constant weight could 

 be obtained at a temperature of 400 C. We found that at this 

 temperature constancy of the weight could readily be reached. 



When the crucibles showed a constant weight at 400 C, chlo- 

 ride solutions of the two carolinium preparations were mixed, in 

 platinum dishes, with a small excess of sulphuric acid. The liquids 

 were then evaporated on a water-bath as far as possible and the 

 resulting sulphates were dried in the platinum-bath devised by Basker- 

 ville and Davis, at about 350 C. They were then placed in the electric 

 resistor- furnace and heated to constant weight at 400 C. 



On account of the discrepancies observed when platinum was used, 

 the determinations were not completed. Quartz crucibles were 

 ordered, and the work will be repeated with them. 



ACETYL-ACETONATES OF THE COMPONENTS OF THORIUM. 

 Charles Baskerviixe with Fritz Zerban. 



Further experiments were made with the acetyl- acetonates of the 

 three fractions, prepared in the same way as described in the last 

 report. A determination of the atomic weight of carolinium, made 

 with the acetyl-acetonate, had yielded the value 239.09. 



As the melting-points of the acetyl-acetonates of berzelium, new 

 thorium, and carolinium had been found to be the same, it seemed 

 desirable to learn whether this fact really proved the identity of the 

 three substances. Since in similar cases a simple determination of 

 the melting-point of mixtures of two substances may be used for 

 deciding this question, the three acetyl-acetonates were mixed in 

 various proportions and the melting-points of these mixtures deter- 

 mined. It was found that the melting-points of these mixtures were 

 exactly the same as observed for the pure compounds. 



Nevertheless this fact can not decide the question of the identity 

 or non-identity of the three substances, because in a very similar case 

 Biltz made like observations. He found the melting-point of neo- 

 dymium acetyl-acetonate as 144 to 146 C, that of praseodymium 

 acetyl-acetonate as 146 C, and the melting-point of didymium 

 acetyl-acetonate, which really represents a mixture of the former 



