t prominent characteristics of its evolution. In the United
Kingdom the conditions of its competition are of a more special kind by
reason of the firm foothold of esparto, which is a most important staple
in the manufacture of fine printings. Whereas the consumption of esparto
remains nearly stationary at about 200,000 tons per annum, the
importation of wood-pulps has shown the extraordinary rate of increase
of doubling itself every five years. But in the group 'wood-pulps' the
trade returns have until recently included the 'mechanical' or ground
wood-pulps. From 1898 we have separate returns for the chemical or
cellulose pulps, and in 1899 the tonnage reached nearly to that of
esparto, with a total money value about 80 p.ct. greater. When it is
remembered that this is one of the newer chemical industries in
cellulose products, and that these large commercial results have been
accomplished during a period of twenty years, we are impressed with the
scope of the industrial outlook to the chemist, afforded by the arts of
which cellulose is the foundation.

It may be noted that there have been no important developments in the
purely chemical processes involved in the several systems of preparing
cellulose from wood. The acid methods (bisulphite processes) have
developed much more extensively than the alkaline, the latter including
the caustic soda and the mixed sulphide ('Dahl') process. The bisulphite
processes depended in the earlier stages upon the efficiency of
lead-lined digesters. But the problem of acid-resisting linings has been
much more perfectly solved in later years in the various types of cement
and other silicate linings now in use. The relative permanency of these
linings has had an important effect on the costs of production. Further
economies result from the use of digesters of enormous capacity, dealing
with as much as 100 tons of wood at one operation. As a combined result
of economic production and active competition, the selling prices of
'sulphite pulp' have moved steadily downwards in relation to other
half-stuffs and raw materials. As a necessary consequence the prices of
those which it has gradually displaced have depreciated, and a study of
the price and tonnage-equilibrium as between rags, esparto, and
wood-pulp over a series of years forms an interesting object-lesson in
the struggle for survival which is an especial mark of modern industry.
For these matters the reader is referred to the special