CARBOX. 65 



And with diamond 



.708 grm. C gave 2.598 grm. CO.^. 2.6695 



.864 " 3-1675 " 2.6661 



1. 219 " 4.465 " 2.6628 



1.232 " 4.519 " 2.6680 



1.375 ■"• 5.041 " 2.6662 



Mean, 2.6665, ± .0007 



Erdmann and Marchand's figures for natural graphite 

 give the following results : 



1.5376 grm. gave 5.6367 grm. CO.^. 2.6659 

 1.6494 " 6.0384 " 2.6609 



1.4505 " 5-3'575 " 2.6647 



In one experiment 1.8935 grm. of artificial graphite gave 

 6.9355 grm. CO2. Ratio for 0, 2.6628. This, combined with 

 the foregoing series, gives a mean of 2.6636, ± .0007. 



With diamond they found : 



.8052 grm. gave 2.9467 grm. CO.^. 2.6596 



1.0858 " 3.9875 " 2.6632 



1.3557 " 4.9659 " 2.6629 



1.6305 " 5-97945 " 2.6673 



.7500 " 2.7490 " 2.6653 



Mean, 2.6637, dr .0009 



Now, combining all these series, we get the following 

 result : 



Dumas and Stas, ist set 2.6683, — .0005 



" 2d " 2.66985, ± .0013 



" 3d " 2.6665, i .0007 



Erdmann and Marchand, ist 2.6636, zt: .0007 



" 2d 2.6637, zh .0009 



General mean 2.66655, dz .0003 



Hence, if = 15.9633, ± .0035, C = 11.973, ± .0030. 



Another very exact method for determining the atomic 

 weight of carbon was emploj^ed by Stas* in 1849. Carefully 

 purified carbon monoxide was passed over a known weight 



* Bull. Acad. Bru.xelles, 1849, ('>) 3^- 



