----------------+-----------+----------- Observer. | Sabin | Pickard | | ----------------+-----------+----------- Wt. of Oil for | 0.5274 | 0.5326 Test, grams | | -----------+----+-----------+----------- | 1 | 0.26 | 12.42 | 2 | 0.51 | 12.39 | 3 | 0.11 | 11.88 | 4 | 2.35 | 11.83 | 5 | 9.14 | 11.08 | 6 | -- | -- | 7 | 14.48 | 10.29 | 8 | 14.48 | -- | 9 | 14.18 | 9.56 Percentage | 10 | 13.86 | -- Increase | 11 | -- | 9.85 in Weight, | 12 | 13.00 | -- in Days. | 13 | -- | 10.30 | 14 | -- | -- | 15 | 12.23 | 10.12 | 16 | -- | -- | 17 | 11.66 | -- | 18 | -- | 10.78 | 19 | 11.07 | -- -----------+----+-----------+----------- Remarks. | | ----------------+-----------+----------- [14] The test of this oil was made without the addition of 5 per cent. of drier, the quantity used in all the other tests. (_b_) DRIER 100 PER CENT. ----------------+-------------- Observer. | { Rogers } | { North } ----------------+-------------- Wt. of Oil for | 0.3445 Test, grams | -----------+----+-------------- | 1 | 48.95 | 2 | 48.53 | 3 | 48.68 | 4 | 48.68 | 5 | 48.48 | 6 | 48.26 | 7 | -- | 8 | 48.43 | 9 | -- Percentage | 10 | 48.89 Increase | 11 | -- in Weight, | 12 | 48.22 in Days. | 13 | -- | 14 | 48.22 | 15 | -- | 16 | -- | 17 | -- | 18 | -- | 19 | -- -----------+----+-------------- Remarks. | Dry at end of | 1st day. ----------------+-------------- CHAPTER III PAINT PIGMENTS AND THEIR PROPERTIES For the student of paint technology, who is not already acquainted with the chemistry and physics of the various raw pigments which are largely used in the manufacture of paints, the writer advises a careful reading of this chapter, in which the matter has been condensed as much as possible. In order to more thoroughly acquaint the reader with the physical constitution of the pigments under consideration, there has been included photomicrographs, which show to advantage the structure of each.[15] [15] The author gratefully acknowledges the assistance of Dr. J. A. Schaeffer in the preparation of the photomicrographs shown in this chapter. [Illustration: By Polarized Light By Transmitted Light Basic Carbonate-White Lead]