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tive with a 6 ring only yielded one-third. Thus while the simple 
cyclic urea derivatives behave like urea the more complex ones 
behave in a different manner. 
4th, Ts it caused by the relative position of the two nitrogen atoms 
in the urea 1.1 or in.other words by their close proximity? To 
throw some light on this problem analyses were male first of all 
of oxamide and symmetric dimethyloramide, in which two nitrogen 
atoms are linked to CO but in the position 1.2, therefore not to the 
same C-atom. The result was that, although by KseLDAHL's method 
all the nitrogen was converted into ammonia, the oxidation process, 
although yielding more than one-half, still showed a considerable 
deficit. Malonamide and succinamide were also investigated. The 
first one with the position 1.3 gave less NII; than obtained by 
KsELDAHL’s method, but the deficit was not nearly so large as in 
the case of oxamide. The second one with the position 1.4 showed 
a somewhat larger deficit. | 
It therefore, appears that the relative distance of the N-atoms 
from each other has an influence on the deficit. 
This agrees with the result yielded by an amide of an amino- 
acid, asparagine, which also showed a deficit; also with that of 
guanidine oxalate which yielded only one-third of the theoretical 
quantity. 
5th, Is the phenomenon also noticed in the case of amides of 
other acids than carboxylic acids such as sulphonic acids? Both 
benzenesulphonamide and benzenesulphondimethylamide were analysed 
and each showed a deficit. 
From the results obtained it is evident that the method of FrirscH 
cannot be used for the estimation of nitrogen without due control 
and that he is wrong in his conclusion that it may be employed in 
all cases where good results are obtainable by KJELDAHL’S process ; 
this is not the case with all amides and not at all with urea deriva- 
tives. It also appears that, when using KJELDAHL’s method, an oxi- 
dising agent such as chromic acid may cause a danger of finding 
too little nitrogen. 
Although this phenomenon depends perhaps within certain limits 
on circumstances. which it is not always possible to control 
and which will cause the figures obtained to constantly vary, still 
it appears that the structure of the nitrogen compound, namely the 
relative proximity of the N atoms exercises a great influence on the 
same, a proximity which may be greater or smaller in open as well 
as in closed chains and depends on their relative position to each 
