a—3a.

PLATE 4. Carbon-paper Impressions ok Ghindek-stone Surfaces.

Fig. II.—Runs Nos. 6 and 7. Stone as left from Run No. 5 cut over with the three-to-the-inch straight-cut burr.

Fig. IV.—Run No. 9. Stone as left from Run No. 8 cut over lightly with the eight-to-the-inch straight-cut burr.

Fig. VI.—Run No. 12. Eight-to-the-inch straight-cut burr.

Fig. I.—Runs Nos. 1 to 5 inclusive and first part of Run No. 8. Eight-to-the-inch straight-cut burr.

Fig. III.—Last part of Run No. 8. Three-to-the-inch straight-cut burr cut over lightly with the ten-to-the-inch spiral burr.

Fig. V.—Runs Nos. 10 and 11. Stone as left from Run No. 9 cut over with the ten-to-the-inch spiral burr.

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