The tests to which the "India" paper was subjected at the Paris Exposition in 1900 also show its most remarkable capacity. In those tests a volume of 1,500 pages was suspended for several months by a single leaf as thin as tissue and, at the close of the exhibition, it was found that the leaf had not started, the paper had not stretched, and the volume closed as well as ever. A strip of this paper, three inches wide, sustained a weight of twenty-eight pounds before yielding. This indicates its extreme tensile capacity. By the use of this paper a book of a thousand pages may be brought within the limits of three-quarters of an inch in thickness--the paper being of such degree of opaqueness as to make possible a beautiful typography on both sides of the sheet and of such strength and durability as to sustain long continued use. The following is a publisher's advertisement of a teacher's Bible: "Printed on genuine India paper, which measures only five-eighths of an inch to 1,000 sheets, making a beautiful, light-weight, convenient book." The fine editions of the Bible (for use and not as a curiosity of the printer's art) and the great Encyclopedia Britannica, printed on India paper are conspicuous examples and embody both the paper maker's science and the printer's art. XI OTHER MATERIALS OF LITERATURE Besides the materials already mentioned, other substances were utilized upon which to impress or embody literature or any historical data. Thus, sections of the bamboo; the leaves and bark of trees and plants as the linden, birch, and the palm; tablets of wood, ivory, gold, bronze, tin, lead, and wax; sheets of silk and linen; sun-dried and fire-burnt bricks; tablets and cylinders of clay; and slabs and stelai of stone, were each and all used in variable proportions, according to taste or necessitous conditions. Of the materials used in picture writing of the ancient Aztecs of Mexico, Prescott says: "The manuscripts were made of different materials, cotton cloth or skins nicely prepared; a composition of silk and gum; but for the most part a kind of paper from the leaves of the maguey."[33]