Grade 2
(a) Grade two is made of a better grade of cotton and with a closer weave than the preceding, but is not sufficiently strong to be used for full binding. It can be used more satisfactorily than the preceding on the sides of books bound in leather or duck. In common with all cloths, except the buckram made according to the government specifications (which will be discussed later), the different colors are not made, as one might suppose, by dyeing the cloth after it is woven, but by mixing the color with the sizing or starch which is used in finishing the cloth, and pressing it into the cloth by machinery. As a natural result the color rubs off with wear and the natural gray of the original cloth as first woven appears. "Art canvas" made by the Interlaken Mills, "Classic buckram" made by the Holliston Mills, and "Polished buckram," by the Joseph Bancroft & Sons Company come within this grade.
(b) Buckram. Under the name of buckram various grades of cloth are manufactured which resemble to a greater or less degree those mentioned under Grade 2 (a). Generally it is a coarsely woven cloth stiffened with glue or sizing, and the term originally indicated that the cloth was made of linen. At the present time linen buckram made in England can be obtained, but all that is manufactured in the United States is made of cotton. Linen buckram costs much more than cotton and it is doubtful if it is any more serviceable. All of the three manufacturers mentioned make buckrams.
Grade 3
Prior to 1907 the Congressional set of government documents distributed to the depository libraries had been bound in sheepskin and the leather on the volumes had disintegrated so much as to make the set a hard one to care for. In 1907 the Congressional Printing Investigation Commission asked librarians of depository libraries to suggest, without considering cost, suitable binding materials for Government Documents. The number of replies received was 124, embodying suggestions as follows: full sheep, 11; half-russia, 78; cloth, 25; buckram, 70; linen duck, 20; canvas, 19. Some librarians expressed more than one preference, so that the total number of preferences was greater than the total of those replying. Most of those who favored sheep did so because of their desire for uniformity. Those who favored half-russia undoubtedly desired half American russia, or cowhide. 134 expressed preference for some form of cloth.
After receiving the replies from librarians the Printing Investigation Commission obtained samples of cloth from various cloth manufacturers in the United States and the Bureau of Standards made a series of chemical and physical tests to determine the durability of these cloths. Chemical tests were made to discover whether the colors were fast when exposed to light. It is to be regretted perhaps that no tests were made to determine whether the cloths were fast to water and that this qualification was not included in the final specifications. Admitting, however, that a cloth which is fast to sun and water both is a valuable cloth for bookbinding, it is evident that the quality of fastness to water is not a vitally important one for cloth used in the United States. The total number of books injured by water is so small as to make insistence upon this quality entirely unnecessary. If books become so soiled that they need to be washed they should be bound in waterproof cloth.
Because many volumes of Government Documents are sent to Porto Rico and the Philippines where insects eat almost anything of an animal or vegetable character, the desirability of the cloth as an article of diet for insects, was also tested.
The physical tests indicated:
a. Number of threads per inch of warp and weft.
b. Absorption of moisture.