It would seem from the above determinations that charcoal, or
some material very high in carbon, usually constitutes a part of the
carbonaceous matter that is left in the first treatment with hydrogen
peroxide. Other more resistant carbonaceous substances may also
be present. It is not known whether l^his resistant matter is high or
low in carbon. The residues obtained in the analyses of Hagerstown
loam, Houston black clay, and Sharkey clay by the standard method
were found to contain insufficient nitrogen to give a test. It is
probable, therefore, that the resistant matter contains no nitrogen.