The relations from which Young's m odulus may be co mpu!'ed from mec ha ni cal fl ex u ral and longitud inal resonan ce freq uencies have been estab lis hed by an em pirical method us ing two sets of steel bars. Both sets co ntain ed rectangu lar a nd cy lindrical specim ens. l ror lon g itudinal vibration of cylindrical specim en , t he ag ree ment between t he empirical curves a nd Bancroft's correspondin g t heoretical relation was wi thin experi mental error if Poisson's ratio for both sets is taken to be 0.292. For flexu ra l vibration s, t he ag ree ment between t he empirical curve a nd the corres pondin g t heoretical relation developed by Pickett is also within experim ental error for abou t t he sam e valu e of Poisson's r atio for the rectangul a r specimen s of both sets ; but for cylindri cal specimen s, t he empirica l values are somewh at lower t han tho e pred icted by the theory.

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A description is given of a series of transverse tests of perlite concrete slabs reinforced with welded wire fabric. The purpose of the tests was to determine the properties of such slabs subjected to short-term and long-term loads. The effect of the reinforcement and the formboard normally used with roof slabs of perlite concrete was investigated.In the short-term tests the slabs were loaded to complete failure, whereas the specimens subjected to the longterm test were loaded with one-half of the estimated maximum load.The results indicate that the minimum concrete strength must be about 1+00 psi in order to develop the full strength of the 1|" by 4in. 12/12 ga welded wire fabric used in the 3-in. thick slabs tested on 36-in. span.The slabs tested under a sustained load for 200 days showed increases over the instantaneous deflections of about 280 and 350 percent for the 230 psi and the 665 psi concrete, respectively, although the instantaneous deflections of the two slabs were nearly equal.

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This paper presents a resume of current practice in the U.S. with regard to the use of sandwich panels in single-story buildings. Descriptions and properties of typical paper honeycomb cores are given. Some of the factors which are considered in choosing sandwich facings and adhesives are given.