2oo 



PEOCEEDINGS OF THE AMERICAN ACADEMY. 



The loss in weight of the salt found in this way is caused in part by 

 a slight sublimation during the fusion, the magnitude of which was not 

 determined in the first series of experiments. Since the neodymium 

 chloride employed in the moisture determinations was not of so high 

 grade of purity as that used in the chloride analyses, the volatilized 

 material probably consisted in part of other chlorides. Hence the pro- 

 portion of moisture calculated from the loss in weight is certainly a 

 maximum. In a second series of experiments, after the fusion of the 

 salt, the sublimate in the quartz tube was dissolved in water and the 

 solution was evaporated to dryness in the weighed platinum boat, and 

 after drying at 135° in hydrochloric acid gas the boat was reweighed.^ 

 The weights thus obtained were subtracted from the loss in weight of 

 the salt found in the same experiment. When the quartz tube was 

 heated alone in hydrochloric acid gas, no sublimate was formed, showing 

 that the volatilized substance did not come from the quartz. 



It is to be noted that the percentage loss in weight 'in the second 

 series of experiments is identical with that of the first series, although 

 the per cent of moisture is less than half the percentage loss in weight 

 during fusion. The effect upon the atomic weight of neodymium of 

 correcting for the moisture is to lower the atomic weight by eight thou- 

 sandths of a unit. 



The percentage of moisture found is nearly identical in magnitude 

 with that obtained from iodine pentoxide which had been made by 

 efflorescence of iodic acid, 0.0023. ^ 



The fused neodymium chloride seemed to be perfectly soluble in 

 water, the probable reason for the better success in these experiments 

 than in the earlier ones being the more efficient drying of the salt 

 before fusion. 



^ The moisture retained by neodymium chloride at this temperature is 

 only 7.5 per cent of its weight. A higher temperature was avoided in order 

 that no portion of the residue might volatilize. 



2 Baxter and Tilley, Jour. Amer. Chem. Soc, 31, 212 (1909). 



