Rotatory Polarization of Liquids. 417 



already found with the two liquids given me by M. Berthelot. 

 It is probable, as I have remarked, that these differences are con- 

 nected with the mode of molecular grouping — which is not the 

 same in the three substances, as is shown in M. Wurtz's che- 

 mical formulae above given. The boiling-points, too, follow the 

 same order as the rotatory powers : that of the acetate is 138°, 

 that of the valerate 133°, and that of the butyrate 128°. On 

 the contrary, the densities do not seem to have any influence on 

 the phenomenon ; for that of the valerate (0894) is greater than 

 that of the acetate (0880), though it is true that the density of 

 the butyrate is the least of the three. It ought to be remarked 

 that the valerate of ethyle has a rather strong natural rotatory 

 power, 1° 30' for a length of 10 centims. : this property does not 

 seem to have any connexion with the magneto-rotatory power, 

 since as to this the valerate is placed between the acetate and 

 the butyrate, which have no sensible natural rotatory power. 



I pass to two other isomers, amylic alcohol and hydrate of amy - 

 lene, the general formula of which is, according to M. Wurtz, 

 C 6 H 12 0. Amylic alcohol has, like the valerate of ethyle, a 

 rather considerable natural rotatory power (l°40'); but this 

 power is exercised in the opposite direction ; it also appears not 

 to affect the magneto-rotatory power. 



Three series of experiments were made upon each of these two 

 liquids. The following are the results : — 



Amylic alcohol. Hydrate of amylene. 



Alcohol. Water. Ratio. Hydrate. Water. Ratio. 



9 40 



10 



0-967 



8 20 



8 40 



0-961 



9 20 



9 40 



0-966 



7 55 



8 16 



0-958 



9 15 



9 35 



0-965 



8 



8 20 



0-960 



Mean . . 0*966 



Mean . . 0-960 



Thus it would appear that the magneto-rotatory power of 

 amylic alcohol is slightly higher than that of hydrate of amy- 

 lene*. Let us notice again that the boiling-point of the first 

 (132°) is higher than that of the second (104-105°). With re- 

 gard to the densities, they differ little — that of amylic alcohol 

 being 0*818 at 15°, and that of hydrate of amylene 0*826 at 0°. 



M. Wurtz kindly sent me also two other isomeric liquids, 

 amylamine and isoamylaminef, which have in common the formula 



* I ought to mention that the length of the column of amylic alcohol 

 was 8 centims., while that of the hydrate-of-amylene column was only 4 

 centims. ; but in each case the water column was of the same length as that 

 of the liquid with which it was compared, which makes the ratios quite 

 correct. 



t The column of amylamine was 6 centims. long, that of isoamylamme 

 only 4 ; but, as before, the length of the water column corresponded. 



