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KXl'ANSloN1 OK lko\, KIT. ,^5
shown. D is an arm of which there are two, one be-in^' attached to each side of the llask through which the pin A is inserted to jjdve a fulcrum for tin* indiea tor arm Iv to revolve on as the one-half-inch stjuare bar expands.
The length of the lever 1C is seventy-two inches at the lon.n' end and the short end should read onr and one-quarter inches instead <»f two inches, as shown. The dotted line of the indicator shows what the arm moves at the time of expansion. ff measures about one-half an inch, sometimes ^'oini;' over this mark, and sometimes a little under it, thus disproving the lotfie. that small bodies or test bars will not expand, as claimed by some. It makes no difference how lnns;c or small a body is, the same law is effective in all cases of metal cooling from a liquid to a solid body,
By referring to Chapters LIY, and LV., pai'cs ,;<*:••; and ,i~.j, two other devices originated by tlu* author for recording expansion can also be seen, Thcsr d»'vicf; ]>vc*sent expansion tests which show the reason b»r there beiii]4' no practical diliVrrncr in the :.p«M-iiir gravity of the two ends csf' vt-rtieal p"Ut'rd e.r.l iuj'j;. a--, can be seen in Chapter LII,,pa^r jMi, Thru a^isiin, I)y referring to (liaptcr L1V,, paja* ,\<).\ tbc cj'fc-cts of expansion in causing* shrink holes in castings arc j'tillv outlined. broken and contraction had begun.