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A description is given of a new hydraulic rapid-loading machine, which is capable of applying a predetermined compressive stress in a time of the order of a few milliseconds and maintaining this stress constant up to and during the subsequent yielding of the specimen. Results of tests on mild steel are presented, giving the variation of yield delay time with applied stress and ferrite grain size. These results are discussed and interpreted in terms of two proposed yield models based on dislocation theory. The effect of grain size on the static yield behaviour is also considered.

The article discusses the factors that put pressure on J. Amos, Jr. as successor to his father's business, The Jones Manufacturing Company, as of 1921. It mentions the purchase of a bill of raw material during Joshua's day. The reason why the company cost 137,000 U.S. dollars to write its inventory down to actual values is also noted. J. Amos' effort for municipal work is also discussed.

The investigational work described in Part I of the paper includes tensile results obtained from “short-time” high-temperature tests of ten different aluminum casting alloys and very pure cast aluminum, and for various heat treatments in the case of some of the alloys. All the specimens tested were sand cast and include the more common commercial casting alloys of aluminum. Tensile strength, yield point, elongation in 2 in., reduction in area, and Young’s modulus values are given for various temperatures throughout the range 75–800 deg. fahr. A typical set of stress-strain curves are given for one alloy, and detail curves showing the effects of temperature on the tensile strength, yield point, and reduction in area for all the materials discussed. An average curve and formula are given, showing the effects of temperature on Young’s modulus for all aluminum alloys. Data are presented to show how certain effects of temperature on aluminum alloys susceptible to heat treatment may be appreciably modified by still further heat treatment or artificial aging. A method is indicated for applying experimental results from a single lot of specimens to commercial-product average values, together with a complete table of recommended tensile-property values at various temperatures for the alloys tested. The second part of the paper describes the original heating equipment, the alternate tests and alterations to equipment to determine and improve the temperature uniformity throughout the specimen; also the method of measuring the specimen temperatures during tensile tests, data being presented to substantiate the reliability of this method. Consideration of the results of temperature-distribution tests made with the final arrangement of the heating equipment and the temperature-measuring equipment used for tensile tests, indicates that an accuracy of temperature measurement of plus or minus 1 per cent and a maximum temperature differential throughout the specimen of 10 deg. fahr. are obtained.