on Magnetic Rotatory Polarization in Gases. 

 Table {continued). 



411 



Series. 



Average 

 :empera- 

 ture, t. 



Average 



pressure, 



H. 



Correction, 



(1+O760 



H. 



Numbers] 

 observed and 

 corrections. 



Corrected 

 magnetic 

 rotations. 



Mean 

 devia- 

 tions. 





2nd image (5 passages). 







Measurement with the glasses. 





March 6, 1880. 



33-6 



millim. 

 821-0 



1-038 



7-20 

 Corr. 3-47 



Diff. 3-73 



\ 3-97 



d-6 





Blue light. — 1st image (3 passages). 







Measurement without the glasses. 





March 19, 1880. 



36-9 



766-1 



1-126 



310 



Mirrors 0-43 



I 3-00 



03 











Diff. 2-67 i J 





Oxygen. — The oxygen was prepared by mixing chlorate of 

 potash with a little binoxide of manganese. The greatest care 

 was taken to purify the gas from the chlorine always contained 

 in it : this was done by passing it several times very slowly 

 through a solution of potash, and then over pumice moistened 

 with a concentrated solution of potash. The gas was dried by 

 passing over fragments of pumice moistened with sulphuric 

 acid and then over calcium chloride. 



In this way several hundreds of litres of gas were prepared 

 in bags which had been used for some time; and the oxygen 

 was slowly introduced into the tube by causing it to pass once 

 more through the series of purifying and drying tubes. The 

 oxygen displaced the air, so that eventually the tube was filled 

 with a mixture containing only a few hundredths of impuri- 

 ties. Several methods were employed for analyzing the oxygen, 

 hydrochloric acid and copper being principally used. In this 

 way we obtained for the mixture studied as below: — 



On the 27th of February, 1880, out of 134 vol. of gas, 3*5 

 vol. of residuum, which we may admit to be nitrogen (say 

 0*9739 of oxygen and 0*0261 of nitrogen). After having made 

 the determinations with this gas, a fresh analysis, made on the 

 3rd of March, yielded out of 121 vol., a residue of 3*4 vol. 

 (say 0*972 of oxygen and 0*028 of nitrogen). 



It is to be noted that, between the two series of experi- 

 ments, a fresh quantity of gas was passed into the tube. It 

 may be admitted that we had an average of 0*973 of oxygen 

 and 0*027 of nitrogen. The following numbers were ob- 

 tained : — 



