Journal . failure of the rubber to give themaximum figures attainable at a given time of was found, however, that although considerable variation occurred in the breaking point figures,yet the shape of the curve obtained was remarkablyconstant. This is well shown in the experimentsgiven in Table I. In the above table the ^%idth of the ring cut bymeans of Schopper cutting press was in each case3-75 mm. and was constant. The load per unitcross section (sq. mm.) in all the tables given wastherefore calculated on a ring 3-75 mm. wide, andhaving the thickness of the slabs vulcanised(5 mm. a
Journal . failure of the rubber to give themaximum figures attainable at a given time of was found, however, that although considerable variation occurred in the breaking point figures,yet the shape of the curve obtained was remarkablyconstant. This is well shown in the experimentsgiven in Table I. In the above table the ^%idth of the ring cut bymeans of Schopper cutting press was in each case3-75 mm. and was constant. The load per unitcross section (sq. mm.) in all the tables given wastherefore calculated on a ring 3-75 mm. wide, andhaving the thickness of the slabs vulcanised(5 mm. approx.) which, as stated elsewhere, did notTary more than ±2°o- It will be seen that in the case of A the loadvaries from 44 kilos, up to 51-5. a difference calcu-lated on the latter of over 14%. The extensioikvaries from 1011 to 1039, a difterence of 2-8%. Inthe case of B the load varies from 26 to 31-5, a>difference of 18%. The extension varies from1160 to 1130, a difference of about 3%. DlAGBl^ ZH Itn 3hhrs An examination of the curves in Diagram I, willshow, however, that all the A curves and all theB curves are almost identical. The curve can,therefore be taken as constant for any particularcure of any particular sample. If now a series of cures is carried out on a givenmixing, a regular series of curves is obtained ofregularly increasing initial inclination with increasein time of cure, and a definite relation connects allthe curves of the series. Typical cases of theseseries are seen in Diagram 2 et sequentes. It willalso be noticed that the curves eventually becomerparallel. In the case of undercures the curve often,breaks off too soon for this to be apparent. Theinitial portion of each curve is approximately fine and represents a rapid increase ofextension with a slow but proportional increase inload. The inclination of this part of the curvebears a definite relation to the state of cure. Themedial portion of the curve represents a continu-ously var
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectchemist, bookyear1882
