Materials, but fail to give a clear idea of their comparative Ratios. Plate 27 gives a graphic representation of the Strength and Elasticity under various strains, which, appealing to the eye, will convey a more definite impression.

(964.)" Weight of Materials."-For convenience of reference, and in order to make this work as complete and self-contained as possible, the Weight of many Materials used in the Arts is given by Table 151, which has been taken from the Author's Treatise on Heat.'

TABLE 151,-Of the SPECIFIC GRAVITY and WEIGHT of MATERIALS Water at 62° being 1·000.