by acid products of bleaching--e.g. oxycelluloses or chlorinated
derivatives; again, by the changes of starch used as a 'sizing' agent,
or by oxidations induced by rosin constituents when the rosin is used in
excess. Discolouration is an attendant phenomenon of these changes, but
is more frequently due to the presence of the lower-grade celluloses
(esparto and straw) and the lignocelluloses (mechanical wood-pulp).

The physical and chemical qualities of papers depending primarily upon
their fibrous or pulp basis, and in a secondary degree upon the kind and
proportion of the constituents added for the purpose of filling and
'sizing,' the report concludes with the following recommendations,
positive and negative, under these heads:

The Committee find that the practical evidence as to permanence fully
confirms the classification given in the Cantor Lectures on 'Cellulose,'
1897 [J. Soc. Arts, xlv. 690-696], and which ranges the paper-making
fibres in four classes:

(A) Cotton, flax, and hemp (rhea).

(B) Wood celluloses, (a) sulphite process and (b) soda and
'sulphate' process.

(C) Esparto and straw celluloses.

(D) Mechanical wood-pulp.

In regard, therefore, to papers for books and documents of permanent
value, the selection must be taken in this order, and always with due
regard to the fulfilment of the conditions of normal treatment above
dealt with as common to all papers.

The Committee have been desirous of bringing their investigations to a
practical conclusion in specific terms--viz. by the suggestion of
standards of quality. It is evident that in the majority of cases there
is little fault to find with the practical adjustments which rule the
trade. They are, therefore, satisfied to limit their specific findings
to the following--viz. (1) normal standard of quality for book-papers
required for publications of permanent value. For such papers they
specify as follows:

Fibres: Not less than 70 p.ct of fibres of class A; class D excluded.

Sizing: Not more than 2 p.ct. rosin, and finished with the normal
acidity of pure alum; starch excluded.

Loading: Not more than 10 p.ct. total mineral matter (ash).

(2) With regard to written documents, it must be evident that the proper
materials are those of class A, and that the paper should be pure and
sized with gelatin, and not with rosin. All imitations of high-class
writing-papers which are, in fact, merely disguised printing-papers,
should be carefully