MOI'M) VS. SOl'AKK TKST HANS. 487
conditions it presents over a square bur in permitting iron to show a uniform ^rain in a test specimen. Xo one need accept the illustration of this question as exhibited by the cuts (Fii^s. 107 and ioS), as any founder can cast stpiare and round test: bars to ascertain the difference in the <4"rain of two such fractures for himself.
For testing iron, by means of roii^h east bars, 1 am at a loss to conceive how anv oiu* with the fails before liiin, as herein set forth, can seient ilieall v support or arctic for the adoption of a square test bar. When we consider the uniformity of radiation, crust, and ;;raiu, that a round bar cast on end makes practicable, and then look at a square bar cast ilut, it does set-in that we do not need any science but that a little* use of fair reasoning is alKsuilieient to^'uide us aright in deciding which of the two forms is the more liable to most closely approximate comparisons of the strength or contraction of iron mixtures, etc/.
The Author's continued advocacy of the round bar, cast on end, since iSX<j has In-en rewarded !»v tin-American Foundrviurn's Assoeiat ion, at it?, annual convention in igoi, unanimously passim; ivsuhit ions recommending the round bar cast on end as the most suitable for test in;,; cast iron. This n-NoJnli«»n also recommends that bars should not In* smaller titan one and one-half inches diameter. The somitT all coiiu* to ivcoj^ni/f the advisability of adopt in^1 tlir abovr ret'oin* nu'ndutions, though many may «lt*sin% to use as small as i 'ij-itu'h cliami'trf bars, which may oft«*n bt* juTinis-sibli- with soft grades, th«' brttrr for all hjtnvstrd in or making tise of test rcH,'ords, An aeeount of the.* A, F. A.'s work in brin^'iuv,' about the abo\c- rei'nm-iiH/iidatioiis is found in Chapter I,XX,, par,*-*; :;y.| in r,.s.j. and attacked the usual formulae for loaded beams asound burs..........................*fi$7 "