296 TRANS. ST. LOUIS ACAD. SCIENCE. 



aloLis expansion of bismuth is ^ that for water, cannot easily be 

 established. That it is considerably less than the anomalous ex- 

 pansion of water is quite certain from our data. 



The bismuth used throughout these experiments was the C. P. 

 preparation of Merck. 



The mercury vapor in the bulbs of the dilatometers amounts to 

 only a few hundredths of a percent of the bismuth introduced, 

 and could not have exercised any great influence on the experi- 

 ments. 



Mr. G. Vicentini ("Sulla variazione di volume di alcuni Me- 

 talli," etc., Torino, 1SS6), experimenting also by the dilatometric 

 method, obtained results which differ in every respect from mine, 

 and it will be necessary to give herewith his results and a criti- 

 cism of his method. He finds the mean co-efficient of dilatation 

 of fused bismuth between the temperature of fusion and 300° C. 

 to be cc = 0.0001 13, or very nearly three times the value given 

 as result of my experiments. 



He also finds that bismuth has its maximum density in the 

 fused state at the temperature of solidification, therefore has no 

 anomalous expansion as is the case with water. 



The following are the tssential dimensions of his two dilatome- 

 ters differing most from one another in sensitiveness. IV is the 

 volume in cub. cent , and w the volume of one division of the 



scales. 



I. II. 



W= 6.278 4-1965 



iu = 0.C0667 0.802498 



The sensitiveness of my dilatometer No. I. is 6. i times as great 

 as No. I. and 3.5 times as great as No. II. of Vicentini's dila- 

 tometers. It is apparent, therefore, that the anomalous expansion 

 of bismuth in Vicentini's most delicate dilatometer would be ^ of 

 one division of his scale if my results are numerically correct, 

 which, considering the difficulties attending the observation from 

 a variety of causes, would no doubt be very likely overlooked. 

 The anomalous expansion of water in that same dilatometer would 

 only be apparent by a rise of ^ division on the scale. I think, 

 therefore, that we are justified in the conclusion that the dilatom- 



