414 M. H. Becquerel's Experimental Investigations 

 numbers relating to the third white image. We have: — 



Air, 0-208 + 0-792 N 544 



0-208 oxygen 0-95 



whence 



0*792 N 4-19 



and N (3rd image) 5*29 



N (4th image) 6-80 



This number agrees sufficiently well with the direct determi- 

 nations ; for we cannot count on a greater precision. 



Nitrogen Monoxide. — Nitrogen monoxide was prepared by 

 the decomposition of ammonium nitrate, and collected over 

 water saturated with this gas. It was subsequently passed into 

 the tube, which was then full of a mixture of 0*70 of oxygen 

 and 0*30 of nitrogen. 



The gas was analyzed by absorbing it by water ; in this ana- 

 lysis account must be taken of the air dissolved in the water, 

 and which is evolved on the solution of the gas which is more 

 soluble. In this way we obtained for the mixture : — 



Nitrogen monoxide 0'691 



Nitrogen 0*219 



Oxygen 0*090 



Cold phosphorus was employed for the analysis of the mix- 

 ture not absorbed by the water. 



The gas, as we see, was very impure; and this disadvantage 

 must be attributed to the air dissolved in the water of the 

 gasometer, and which was evolved, either by a partial vacuum 

 being produced in the upper part of the gasometer, or by the 

 solution of nitrogen monoxide in the water. 



The following numbers were obtained for the preceding 

 mixture : — 



Series. 



Average 

 tempera- 

 ture, t. 



Average 



pressure, 



H. 



Correction, 

 (l+at)760 



Numbers 

 observed 

 and cor- 

 rections. 



Corrected 

 magnetic 

 rotations. 



Mean 

 devia- 

 tions. 



H 



Jan. 30, 1880. 

 Jan. 30, 1880. 



23-0 

 26-9 



White 



millim. 

 772-0 



Green ] 

 774-0 



LIGHT. 4th 



1-067 



jIGHt. — 4th 

 1-067 



image. 



lflO 

 Corr. 4-58 



Diff. 12-52 



image. 



21-12 

 Oorr. 6-13 



Diff. 14-99 



1 13-36 

 t 15-99 



i-7 



4-2 



