|{days| | | | | | | | | | | |{15 |0.466|0.455|0.650|2.41 |11.05 | -- |7.92 |10.50 |9.30 | -- | -- |{days| | | | | | | | | | | |{20 |0.521|1.08 |1.78 |8.76 |11.25 |10.67 |7.98 |10.52 |9.36 | -- | -- |{days| | | | | | | | | | | =====+=====+=====+=====+=====+=====+======+======+=====+======+=====+====+==== TABLE IX--LINSEED OIL AND PbO (LEAD) AND MnO_{2} (MANGANESE)--COMBINATION DRIER =================+========+=====+=====+======+======+====+=====+==== Per cent. PbO | | 0.1 | 0.3 | 0.5 | 0.7 |0.9 | 1.1 |1.4 -----------------+--------+-----+-----+------+------+----+-----+---- Per cent. MnO_{2}| |.005 |.015 | 0.025| 0.35 |0.45| 0.55|0.7 -----------------+--------+-----+-----+------+------+----+-----+---- |{ 1 day |0.026|0.061| 0.055| 0.022|0.16| 0.11|3.06 |{ 2 days|0.094|0.087| 0.143| 0.16 |5.21| 6.28|3.37 |{ 3 days|0.118| -- | 0.17 | 4.23 |7.63| 8.31|3.74 |{ 4 days| -- |0.11 | 0.23 | 7.36 |8.87| 9.20|4.02 |{ 5 days|0.120|0.12 | 0.29 | 9.04 |9.13| 9.37|4.17 Per cent. gain |{ 6 days|0.17 |0.13 | 1.44 | 9.88 |9.26| 9.51|4.34 |{ 7 days|0.21 |0.18 | 4.65 |10.11 |9.28| -- |4.45 |{11 days|0.30 |0.26 |10.03 |10.35 |9.61| 9.85|5.11 |{12 days| -- | -- | -- |10.45 |9.66| -- | -- |{13 days|0.35 |0.54 |10.37 |10.51 |9.67|10.03|5.33 |{18 days|0.49 |3.43 |10.38 |10.62 |9.68| -- |5.73 =================+========+=====+=====+======+======+====+=====+==== In the same way with lead driers, excessive amounts of lead oxide seem to have no beneficial effects on the drying of an oil, and when the percentage which seems to be the most beneficial, namely 0.5% lead oxide, is exceeded, the film is apt to become brittle. Oils containing lead oxide driers are less influenced in their drying tendencies by conditions of moisture in the atmosphere than oils containing manganese, but frequently, however, the former dry much better in a dry atmosphere. As a general rule, varnishes rich in manganese dry more quickly in a dry atmosphere, while those containing small quantities dry more quickly in a damp atmosphere. =Volatile Products Formed.= It was furthermore noticed in these tests that sulphuric acid, placed in dishes on the bottom of the large box in which the samples of oil were drying, was discolored and turned brown after several days, showing that the acid had taken up some material of a volatile nature that was a product of the oxidation.