Bookbinding and the Conservation of Books
A Dictionary of Descriptive Terminology

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equivalent weight

1. The weight of a particular paper of any size expressed in terms of some other size. Equivalent weights are in direct proportion to the areas of single sheets. If the weight of a given size of paper is known, the equivalent weight of the paper of a different size can be calculated by multiplying the known weight of the paper by the area of the paper required and dividing by the known area of the paper:
Weight of paper of which      Area of paper of which
size and weight are known  X  weight is required
-------------------------------------------------    = equivalent weight
Area of paper of known weight

Thus, the weight of a ream of paper 5 x 40 inches in the substance of 30 to 40 inches, 60 pounds per 500 sheets is:

    60 X (25 X 40)
     -----------
      (30 x 40)
= 50 pounds/500 sheets, 25 x 40 inches.

2. In chemistry, equivalent weight is one of the comparative weights of different compounds, elements, or radicals which possess the same chemical value for reaction when compared by reference to the same standard (usually oxygen, i.e., 8).

Parallel lines also outline a center panel. All of the lines, both horizontal and vertical, cross near the extreme ends forming squares at the corners of the covers. The central panel is usually decorated with a pattern made up of small, almost touching, tools, and both borders are similarly decorated with a succession of tools; those of the broad inner one often are interrupted with a scroll bearing the name of the bookbinder. Many bookbinders of the latter half of the 15th century produced these so-called Erfurt bindings, includingCONRADUS DE ARGENTINA and JOHANNES FOGEL . (141 )

In an acid, the equivalent weight is the quantity which would yield one gram ionic weight of hydrogen ion (1.008 g.), while in a base, it is the quantity which would yield one gram ionic weight of hydroxyl ion (17.008 g.). Thus an equivalent weight of sulfuric acid (H 2 SO 4 ) is one-half the molecular weight, and an equivalent of aluminum hydroxide (Al(OH) 3 ) would be one-third the molecular weight. (17 , 58 , 139 , 195 )




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