Ratio between 



Ratio between 



the densities. 



the rotations. 



1-0224 



1-0222 



1-059 



1059 



1-036 



1-036 



408 Prof. A. De la Rive's Researches on the Magnetic 



Iodide of Ethyle. 

 Temperature . Rotation . 



12 C. 20 40 



3L „ 20 13 



59 „ 19 30 



Temperatures. 



12 and 31 

 12 „ 59 

 31 „ 59 



Amylic Alcohol. 

 Temperature. Rotation. 



15 C. 9° 30 



30 „ 9 22 



35 „ 9 20 



Temperatures. Ratio between Ratio between 



the densities. the rotations. 



15 and 30 1014 1-014 



15 „ 35 1-019 1-018 



Thus, then, as in the case of rectified alcohol, the diminution 

 which a rise of temperature occasions in the magneto-rotatory 

 power of iodide of ethyle and in that of amylic alcohol will be 

 proportional to the corresponding diminution of density. Of 

 these liquids, again, 1 determined the ratio between the densi- 

 ties by means of the ratio between their volumes, at different 

 temperatures, as given in the Tables prepared by M. Isidore 

 Pierre*. The results obtained with alcohol are the most con- 

 clusive, being derived from experiments upon a greater range of 

 temperature and at the same time more numerous. Neverthe- 

 less both series indicate that, if the law to which they seem to 

 conduct is not absolute, it is at any rate very nearly accurate, at 

 least within the limits of temperature within which the obser- 

 vations took place. If, then, we could strictly prove that the 

 magneto-rotatory power of every liquid at a determined tempe- 

 rature is proportional to its density at the same temperature, we 

 should arrive at the conclusion that this power is molecular and 

 remains the same for each molecule, whatever the physical con- 

 ditions in which it is placed; and the deduction from this would 

 be, that the magneto-rotatory power of a body is only the sum 

 of the magneto-rotatory powers of the particles of which it con- 



* Annates de Chimie et de Physique, S. 3. vol. xv. p. 354, and vol. xix. 

 p. VJV et seqq, 



