Iron corrosion; anti-fouling and anti-corrosive paints . ughly corroded iron plate : atmospheric actiou. hours (Fig. 9) produces a coherent crust, of fairly regulardepth, which has already begun to peel off. Below thisincrustation is a secondary formation of rust, so that whenthe upper crust falls off or is dissolved, a new layer will befound, which, however, takes much longer to arrive at thepeeling-off stage. When dilute hydrochloric acid is left to act for only ashort time (Figs. 10 and 11) there is formed a coherent layer of mON-COBEOSION AND ANTI-COHROSIVE PAINTS. 43 rust of a fairly UDif
Iron corrosion; anti-fouling and anti-corrosive paints . ughly corroded iron plate : atmospheric actiou. hours (Fig. 9) produces a coherent crust, of fairly regulardepth, which has already begun to peel off. Below thisincrustation is a secondary formation of rust, so that whenthe upper crust falls off or is dissolved, a new layer will befound, which, however, takes much longer to arrive at thepeeling-off stage. When dilute hydrochloric acid is left to act for only ashort time (Figs. 10 and 11) there is formed a coherent layer of mON-COBEOSION AND ANTI-COHROSIVE PAINTS. 43 rust of a fairly UDiform dark rust-brown colour. Only in afew patches, where the surface produced by rolling has beendamaged, is the uncorroded metal to be seen. No looseningof the rust coating can be detected, a proof that it is rela-tively very thin. In two hours dilute hydrochloric acid produces thickerincrustations of rust (Fig. 14) rather browner in colour. Inthis case also there is no indication of rust warts, neitherhas the peeling, shown in Fig. , yet Fig. 27 (magnified).—Thoroughly corroded iron plate ; atmospheric action. The highly energetic action of common salt as a rustformer is evident from Figs. 17 and 19, almost the entiresurface of the iron in both cases being covered with a rela-tively thick crust, requiring but a very short time for itsdevelopment. There occurs both a uniform surface of rust,and individual rust warts ; and in this case also the peculiarphenomenon of a thicker incrustation round the edges thanin the middle is noticeable. 44 IRON-COREOSION AND ANTI-CORROSIVE PAINTS. In all the preceding experiments, wherein the artificialproduction of rust was effected in order to obtain an insightinto the action of the different agencies, scarcely any furtherprogression of the rusting has been observed, owing to thefact that the conditions of such development were lacking,the samples having been stored in a dry place. Only after
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