885 



what degree tlie differences in size of (lie volume of tlie different C 



atoms would have to be taken into account, I shall not attempt as 



ve^ to calculate the found di(!ereuces iu size, at least not for the 



piesenl. For isohiilyl, uioreoNcr, (lie dillereuce in size auionuls only 



to .'i percent, and it always remains ijie ((ucstion how far the accu- 



lacy of the deleruiiiuitiou of 7/, and fii- has l>een carried, and \n how 



far the absolute purity of the sid»stancc and the e(piality of the factor 



7 X '-273 



can be relied on. I shall there(oi-o tor flif present be 



(1+ a) (!—(./ 



satisfied with the a})proximative calculations, which 1 have used above. 



For the methyl-, ethyl-, propyl-couipounds etc. there is a whole 



series of determinations of Tk and pi which can be of use for the 



calculation of CH.^. Then a new kind of atom, or a new groiiji 



of atoms, which we do not know as yet, is indeed added, but 



when the new group of atoms is bound in these compounds in the 



same way, the difference in — , e.g. for the methyl- and ethyl-series, 



Pk 

 can then enable us to determine the value of CHj. Thus we find the 

 following values : 



Tk Pk ^ CH, 



Pk 



Methyloxide 127,1+273 53 7,55| 5,57 _ 



Ethyloxide 193,8 -f 273 35,6 13,12) ~2 ~ ^''^^ 



Methyl and ethyloxide 1(37,6 + 273 46,27 9,5 



The value 2.78 coming so near the previous determination, I do 



Tk 

 not hesitate to call the value — for the third substance too small. 



Pk 



There the value 10.25 is to be expected instead of 9.5. If one should 



assign the before given value also to the other H and C atoms, 



7' 

 (> = 1,3 woidd follow^ from Üiis, whereas ().^ ^ 3 follows from -. 



Pk 

 Thus we find for : 



From this we should therefore derive CH„ = 2,8. So the abnor- 



