THE 

 LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[FOURTH SERIES.] 



DECEMBER 1870. 



XLIX. Researches on the Magnetic Rotatory Polarization of 

 Liquids. By Professor A. De la Rive*. 



THE present researches are a continuation of those I com- 

 municated to the Society, and published, in 1868 f. In 

 my first memoir I studied the phenomenon of magnetic rotatory 

 polarization in itself, and investigated the causes which exercise 

 an influence on its production and intensity. I showed that the 

 actions which permanently modify the molecular constitution of 

 a solid body (such, for example, as the transmission of a powerful 

 electrical discharge) modify in an equal degree its magnetic ro- 

 tatory power ; while in the case of liquids this power undergoes 

 no modification, whether they are acted upon mechanically or by 

 an electrical discharge or an electric current. I called attention 

 to the influence which seems to be exercised upon the intensity 

 of the magnetic rotatory power by the density of the substance 

 submitted to the action of the magnet, even when this element 

 is not exclusively predominant — citing as an example the consi- 

 derable magnetic rotatory power (the greatest known) possessed 

 by thallic alcohol, the density of which is enormous (sp. gr. 3*55). 

 The new researches just terminated have been made upon 

 liquids only ; for solids present the inconvenience of a molecular 

 constitution too much varying from one to another to conduct us 

 to any general results ; and elastic fluids do not possess sufficient 

 density to render the phenomena in question sensible. 



* Translated from a separate copy communicated by the Author, having 

 been read before the Societe de Physique et d'Histoire Naturelle de Geneve, 

 June 2, 1870. 



f Archives des Sciences Physiques et Naturelles, vol. xxxii.p. 193; An- 

 nates de Chimie et de Physique, 4th Series, vol. xv. p. 57. 



Phil. Mag. S. 4. Vol. 40. No. 269. Dec. 1870. 2 D 



