418 M. H. Becquerel's Experimental Investigations 



In this analysis account must be taken of a small quantity 

 of air that may be introduced by the chlorine, as well as of the 

 air which is evolved from the liquid by absorbing the chlorine 

 through the potash. 



From careful experiments I found, before commencing 

 the first series recorded below, that the gas contained 0*044 

 of air. In the interval between the first and second series, 

 the tube being very hot, a little gas was lost by the closing of 

 the glasses. At the end of the second series two closely 

 agreeing analyses gave 0*061 of impurities. It may be assumed 

 that we had on an average a mixture containing 0*95 of olefiant 

 gas and 0*05 of air. 



A great number of measurements for the different images 

 and colours were made with this body, because the rotations, 

 relatively great, were to serve as verification of our experi- 

 mental method. 



A direct determination made with the yellow light of soda 

 gave, for the first image, a number very close to those which 

 would be deduced from the rotation obtained with the fourth 

 white image. There is no use in giving this number, because, 

 on account of the feeble intensity of the light, it was not pos- 

 sible to ensure the same precision as in the case of the other 

 measurements. 



We subjoin the results of our measurements with olefiant gas. 



Olefiant Gas, 0'95 C 2 H 4 + 0*05 Air. 



Series. 



Average 

 tempera- 

 ture, t. 



Average 



pressure, 



H. 



Correction, 

 (l+a*)760 



Numbers 

 observed 

 and cor- 

 rections. 



Corrected 

 magnetic- 

 rotations. 



Mean 

 devia- 

 tions. 



H 





Whi 



te light. — 4th image (9 passages). 





Feb. 17, 1880. 



193 



millim. 

 804-5 



1012 



35-23 

 Corr. 458 



1 , 



\ 31'01 



5-0 



Diff. 30-65 



Feb. 20, 1880. 



230 



776-2 



1-061 



34-36 



Corr. 4-58 



Diff. 29-78 



[ 31-56 



5-2 







3rd image (7 passages). 





>> » 



320 



797-9 



1064 



27-86 

 Corr. 3-79 



I 25-61 



2-3 



Diff. 24-07 



