[Illustration: Scaled Whiting Films Chemically Active Pigments and Their Effect After Eighteen Months' Wear] [Illustration: Plate Showing Effect of Chemically Active Pigments on Oil after One Year's Wear] =Panel No. 29--Whiting.= Plates coated with calcium carbonate or whiting in oil presented a very fair appearance at the start of the test, but they soon began to chalk and disintegrate. It is well known that whiting, being alkaline, has the property of acting on oil and causing its early disintegration by saponification. As a matter of fact, six months after the whiting plates were exposed, crumbling of the surface appeared, and twelve months was sufficient for the total destruction of the paint. At this time the rusted surface of the plates which had been painted with calcium carbonate, seemed not to rust as fast as those plates which were exposed without paint coatings, and the rust which had formed appeared to be of an even, fine texture. On the lower left-hand corner of these plates had been lettered the figures "29" and "30," using lampblack in oil. One of the most remarkable things which appears on the fence to-day is the perfect condition of these lampblack letters over their priming coat of calcium carbonate, standing out in clear relief against the rusted metal. This test would suggest, therefore, that if the surface of metal is properly protected with a pigment which is slightly alkaline or inhibitive in nature, and then topped with a good weather-resisting material, such as lampblack, graphite or carbon black, good results would be obtained. Further tests will be made to determine the value of this suggestion. =Panel No. 30--Precipitated Calcium Carbonate.= Showed more rapid destruction than Panel No. 29. [Illustration: Corrosion Adhering to Film Stripped from Panel Painted with Gypsum (Calcium Sulphate)] =Panel No. 31--Calcium Sulphate.= Under the paint film of gypsum, rust soon appeared, showing that the film was not a good excluder of moisture. Although the film remained intact, rusting progressed throughout the test and considerably darkened the color of the paint. =Panel No. 32--China Clay.= This pigment gave excellent service for eighteen months. Afterwards indications of corrosion were shown, and apparent breakdown of the film was indicated. [Illustration: China Clay Asbestine Gypsum] =Panel No. 33--Asbestine.= In the same condition as Panel No. 32. [Illustration: Excellent Surface shown by American Vermilion after nearly Four Years' Exposure] =Panel No. 34--American Vermilion.= This pigment has given perfect protection to the plates. The film is strong and elastic, and upon removal reveals the bright steel. No chalking, checking, discoloration, or other signs of paint failure are shown. It would appear that the inhibitive characteristics of this pigment are pronounced, and it promises to give efficient service for several years more.