At
the same time the internal condensation noticed in the acetylation of
the jute appears not to occur in the case of the benzoate.

~Nitric Esters.~--The numbers resulting from the quantitative study of the
ester reaction and product (1st ed. p. 133) show a very large divergence
of the yield of product from that which would be calculated from its
composition (N p.ct.) on the assumption that the ester reaction is
simple. We have repeated the results, and find with a yield of 145 p.ct.
that the product contains 11.8 p.ct. N.

The reaction

C_{12}H_{18}O_{9} + 4HNO_{3} - 4H_{2}O

gives a tetranitrate with 11.5 p.ct. N and a yield of 159 p.ct. The
ester reaction, therefore, is not simple. There are two sources of the
loss of weight. The first of these is evident from the occurrence of
certain secondary reactions which result in the solution of a certain
proportion of the fibre substance in the acid mixture. To determine this
quantitatively we have devised a suitable variation of the method of
combustion with chromic acid (1st ed.).

The variation is required to meet the difficulty occasioned by the
tension of the nitric acid and products of deoxidation. The mixed acids
(10 c.c.), containing the organic by-products in solution, are
carefully diluted in a small flask with an equal volume of water,
preventing rise of temperature. Nitrous fumes are evolved during the
dilution. Strong sulphuric acid (15 c.c.) is now added, and the residue
of nitrous fumes expelled by a current of air, agitating the contents of
the flask from time to time. The combustion with CrO_{3} is then
proceeded with in the ordinary way. The gases evolved are measured
(total volume) and calculated to C present in the form of products
derived from the lignocellulose; and, assuming that this contains 47
p.ct. C, we may express the result approximately in terms of the fibre
substance. The method was controlled by blank experiments, in which
citric acid was taken as a convenient carbon compound for combustion.
The C found was 34.9 p.ct. as against 34.3 p.ct. calculated. By this
method we find that with maximum yields of nitrate at 143-145 p.ct. the
organic matter in solution in the acid mixture amounted to 4.9 to 5.3
p.ct. of the original lignocellulose.

Introducing this quantity as a correction of the yield of nitrate in the
original reaction, we must express the 143 parts as obtained from 95 of
fibre substance instead of 100.

The yield per m