Bulletin . 9 burns isgiven in figure 8. FELDSPAR CLASSIFICATION. 49 This chart indicates that— 1. The pure feldspar deforms between cone 8 and cone 9, being closer to the latter. 2. Around 2 and 3 per cent kaolin the start of deformation is late, the rate is fast, andthe end is before that of pure feldspar. 3. At 5 and 6 per cent the rate decreases until it is about that of the pure feldspar,but the start and end of deformation is behind that of the latter. 4. In the 9 to 11 per cent region there is another slow starting, a rapid rate, and quickfinish to deformation. The rate here is faster th
Bulletin . 9 burns isgiven in figure 8. FELDSPAR CLASSIFICATION. 49 This chart indicates that— 1. The pure feldspar deforms between cone 8 and cone 9, being closer to the latter. 2. Around 2 and 3 per cent kaolin the start of deformation is late, the rate is fast, andthe end is before that of pure feldspar. 3. At 5 and 6 per cent the rate decreases until it is about that of the pure feldspar,but the start and end of deformation is behind that of the latter. 4. In the 9 to 11 per cent region there is another slow starting, a rapid rate, and quickfinish to deformation. The rate here is faster than any other. 5. Beyond 10 per cent kaolin, normal conditions are gradually resumed, the startand finish progressing toward higher temperatures with the increase of kaolin. Cones in which the kaolin impurity varies only by 1 per cent do not show muchdifference in their deformation. Hence regions, instead of definite percentages, mustbe used in terming these indicated eutectics. Kaolin,percent 17 18 19 20. Figure 9.—Diagram showing relation of rate of deformation to proportion of kaolin. Vertical distancebetween lines represents rate of deformation of pure feldspar. Figure 9 shows in a more general way the rate of deformation, that being desig-nated by vertical distances between the two curves. The normal rate—that is, thatof pure feldspar—is represented by the vertical distance between the two dotted linesdropping to the right as the kaolin content increases. CONCLUSIONS. The results of these two charts show that there are two indicated deformationeutectics, the lesser in the region of 2 to 3 per cent kaolin and 98 to 97 per cent feld-spar, and the greater at 9 to 11 per cent kaolin and 91 to 88 per cent feldspar. Corre-spondingly, 5 to 6 per cent kaolin and 95 to 94 per cent feldspar is a region whichmay be termed a deformation compound. When we speak of regions, it is meantthat in the limits given there is a definite percentage at the maximum or minimumpoint which sho
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