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



Sulphurous Acid. 

 I made four series of experiments on liquefied anhydrous sul- 

 phurous acid, taking care that the tube which contained it and 

 the disks which closed the tube should be sufficiently solid. In 

 the first series the magnetization was effected by the current from 

 a Bunsen pile of 60 pairs, in the three others by that from a 

 pile of 40 or 50 pairs. The experiments were singularly con- 

 cordant. Here is the result of the observations of each series: — 



Sulphurous acid. 



Water. 



Ratio. 



15 10 



o / 



12 10 



1-246 



13 40 



11 



1-241 



12 



9 40 



1-241 



13 40 



11 



1-241 



Suspecting that the first result was due to the temperature of 

 the acid being lower, I took sulphurous acid at the temperature 

 of 4° or 5°, and obtained : — 



Sulphurous acid. Water. Ratio. 



14° 11° 1-272 



Then, the acid having attained the temperature of the room 

 (12° or 13°), I again obtained 1*241. 



A series of experiments made a few days afterwards gave again 

 the number 1*241; but the room becoming warmer, the ratio 

 was reduced to 1*233; and at the end of the experiment it was 

 1*207, the temperature of the room having risen to 20° C. 



These variations, so considerable for small changes of tempe- 

 rature, are due to the great dilatability of liquefied anhydrous 

 sulphurous acid. In fact we shall see in the next Section the 

 marked influence exercised by the temperature on the mag- 

 neto-rotatory power of liquids — an influence connected with their 

 dilatability. 



I think, then, we may, without sensible error, take the num- 

 ber ] *240 for the coefficient of the specific magneto-rotatory po- 

 larization of sulphurous acid at 12° C. 



Sulphurous acid dissolved in water in sufficient quantity to 

 saturate it gave : — 



Acidulated water. Water. Ratio. 



12° 11° 1*100 



We know that water dissolves fifty times its volume of gaseous 

 sulphurous acid. Even under the pressure of three atmospheres, 

 gaseous sulphurous acid presented no trace of magneto-rotatory 

 polarization. 



I will only mention, without dwelling upon them, some expe- 

 riments made upon other liquids, particularly the essences. 



The essence of orange and the essence of citron gave me only 



