( ^92 ) 

 Anomalous densities of fused Bismuth. 



By C. LUEDEKING, Ph.D. 



Presented before the St. Louis Academy of Science Dec. 19, 1887. 



Water has, as is well known, anomalous densities. Down to 4° 

 C. it contracts in volume, whilst from 4° to 0° (its freezing point) 

 it presents the anomalous phenomenon of expansion. If prevented 

 from freezing it even continues expanding below 0°, presumably, 

 until it reaches a density corresponding to the density of ice at that 

 especial temperature, when it will contract on further cooling. 

 We have no explanation for this phenomenon that can be called 

 at all satisfactory. 



The phenomenon has been thought to be caused in some man- 

 ner by, or to have a dependence on, the fact that water at the 

 moment of solidification expands greatly ; and it has been sup- 

 posed that ice molecules are formed at these temperatures of 

 anomalous densities, and, remaining in solution, are the cause of 

 expansion of volume. 



However, all other physical constants such as specific heat, 

 optical properties, etc., fail to demonsti'ate that such is the case. 

 We must for the present content ourselves and await further 

 developments of our knowledge of the exact relationship of the 

 molecular states of liquids and solids. 



To my knowledge the case of water stands isolated in respect 

 of these anomalous density phenomena. I have been unable to 

 find any other in the literature at my disposal. It seemed desira- 

 ble to ascertain whether other substances present similar pheno- 

 mena (anomalous densities), and it naturally suggested itself by 

 analogy to select such as also expand greatly on solidification. 



Sulphate of mangnesium and sulphate of sodium are salts be- 

 longing to this category, whilst among metals we have notably 

 bismuth. 



The experimental difficulties in case of the first two substances 

 ?re exceedingly great, and it was impossible to obtain any results. 

 With bismuth the case stands differently, and I beg herewith to 

 describe the mode of experiment and give my numerical data. 



