on Magnetic Rotatory Polarization in Gases. 415 



The rotations which would be given by protoxide in a pure 

 state can be deduced from the preceding numbers; in fact, we 

 have for the fourth image (white light): — 



whence 



Mixture 13-36 



0*219 N V-bl\ 

 0-09 0'-53J 



2-04 



0*691 N 2 11-32 



From this is deduced: — 



N 2 O (4th white image). . . 16'*38 



The same calculation can be made for the green 

 indeed we have for the 4th image (green light) : — 



light; 



Mixture 15*99 



0-219 N V-\ 

 0-99 O 0'*53 



} 



2-41 



0-691 N 2 . 13-58 



whence N 2 O (4th green image) 19-61 



Carbonic Acid. — The carbon dioxide was prepared by the 

 action of hydrochloric acid on white marble. A current of 

 this gas, previously dried, was passed for a very long time into 

 the tube, which contained at the time the mixture of nitrogen 

 monoxide, oxygen, and nitrogen above mentioned. 



This gas was analyzed by absorbing it by water; and out of 

 154 vol. of gas I found a residuum of 3 vol. (say 0-0195 of 

 impurities and 0'9805 of carbonic acid). This gas may be 

 considered pure ; and the numbers obtained can only admit 

 an inappreciable correction ; for it happens that the carbonic 

 acid has very nearly the same magnetic rotatory power as the 

 mixture which constitutes the 0*019 of impurities. The results 

 obtained are given in the following table: — 



Series. 



Average 

 tempera- 

 ture, t. 



Average 



pressure, 



H. 



Correction. 



(1 + O760 



Numbers 

 observed 

 and cor- 

 rections. 



Corrected 

 magnetic 

 rotations. 



Mean 

 devia- 

 tions. 



H 



Feb. 6, 1880. 

 Feb. 6, 1880. 



17-5 

 20-0 



White 

 millim. 

 808-4 



Green 

 815-8 



LIGHT. — 4th 



1-000 



LIGHT. — 4th 



1-000 



image. 



16-90 



Corr. 4-58 



Diff. 12-32 



image. 



21-50! 

 Corr. 613 



1 12-32 

 15-37 



2-7 

 2-6 



Diff. 1537 



212 



