>J 



11 





H 



71 



•3 



5 



11 



11 



a 



6 



7 



11 



11 



11 



13 



11 



11 



8 



11 



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



with great accuracy) 1*842. With this acid and distilled water 

 I made mixtures in the following proportions : — 



9 volumes of water, and 1 of acid : 



7 ,, ,» 3 



5 



4 



3 



2 



I ascertained the magneto-rotatory power of each of these so- 

 lutions ; and I compared this real power with that calculated 

 by taking 0*800 for the magneto-rotatory power of the pure acid 

 and 1*000 for that of water, taking account of the proportions 

 of water and acid in the mixture, and supposing that no change 

 of volume takes place by the act of mixing. I likewise deter- 

 mined the ratio between the actual density of each solution and 

 its density calculated by taking 1*8421 for the density of the pure 

 acid and 1*000 for that of water, and supposing that no change 

 of volume is effected by mixing. 



The following Table, drawn up from the means of a great 

 number of experiments, gives, for each of the solutions, on the 

 one hand the actual and the calculated rotatory powers and the 

 ratio between them, and on the other the actual and the calcu- 

 lated densities and the ratio between these. 



Proportion of acid 



Actual rota- 



Calculated rota- 



Ratio between 



in the solution. 



tory power. 



tory power. 



the two powers. 



0*1 



1*012 



0*980 



1*032 



0*3 



0*975 



0*940 



1*037 



0*5 



0*934 



0*900 



1*037 



0*6 



0*915 



0*880 



1*039 



0*7 



0*888 



0*860 



1*032* 



0-8 



0*875 



0*840 



1*040 





Actual 



Calculated 



Ratio between 





density. 



density. 



the two densities, 



0*1 



1*118 



1*084 



1032 



0*3 



1*316 



1-252 



1-051 



05 



1*553 



1-421 



1*093 



0*6 



1*607 



1-505 



1*068 



0*7 



1*623 



1-590 



1*071* 



0*8 



1*751 



1*674 



1-045 



* The result obtained, both as to the ratio of the actual to the calculated 

 rotation and the ratio of the actual to the calculated density, with the solu- 

 tion containing 7 parts by volume of acid to 3 of water presents an evident 

 anomaly, of which I have not been able to discover the cause ; it is possibly 

 the result of an experimental error, though I am not disposed to think so. 



