The whole of the rod will therefore be subject to a **compressive** longitudinal stress P, the associated contraction R, expressed as a fraction of the original length, being R = P/M = (B 2 -H2)/87-M, where M is Young's modulus.

4 Some writers have indeed contended that the stress in magnetized iron is not **compressive**, but tensile, even when, as in the case of a ring-magnet, there are no free ends.

Rowland in support of **compressive** stress.

The maximum **compressive** working stress on the concrete may be 500 lb per sq.

Folding of the rocks resulted from the operation of great **compressive** forces acting tangentially to the figure of the earth.

The deformation of the Appalachianswas accomplished in two chief periods of **compressive** deformation, one in early Palaeozoic, the other about the close of Palaeozoic time, and both undoubtedly of long duration; the second one extended its effects farther northwest than the first.

The safe tensile strength of Portland cement concrete would be something like one-tenth of its **compressive** strength, and might be far less.

It has considerable **compressive** or crushing strength, but is somewhat deficient in shearing strength, and distinctly weak in tensile or pulling strength.

Such composite structures take advantage at once of the high tensile strength of iron and of the high **compressive** strength of cement mortar.

On examining the diagram it will be observed that the maximum **compressive** stresses are parallel to and near to the down stream face of the section, which values are approximately equal to the maximum value of the vertical stress determined by the law of uniformly varying stress divided by the cosine squared of the angle between the vertical and the resultant.

The vertical distance above the line ab of any point in the dotted line dc is proportional to the vertical component of the **compressive** stress on the line ale assumed to vary uniformly from face to face, and similarly the vertical distance of any point in the3-dot-and-dash line ae above the line ab is proportional to the vertical component of the stress determined experimentally.

There are many structures at present in existence bearing considerably greater loads than this, and the granite ashlar masonry of at least one, the Bear Valley dam in California, is subject to **compressive** stresses, reaching, when the reservoir is full, at least 40 to 50 tons per sq.