Corrosive substance or slowly over days or years, e.g. the rusting of iron in a bridge. Sometimes the word caustic is used as a synonym for "corrosive", but "caustic" refers only to strong bases, particularly alkalis, and not to acids, oxidizers, or other non-alkaline corrosives. At low concentrations, a corrosive substance is called an irritant, and its effect on living tissue is called irritation. At high concentrations, a corrosive substance causes a chemical burn, a distinct type of tissue damage. Corrosives are different from poisons in that corrosives are immediately dangerous to the tissues they contact, whereas poisons may have systemic toxic
Magic cube classes MAY be pandiagonal magic. Gardner also called this (Langman’s pandiagonal) a ‘perfect’ cube, presumably not realizing it was a higher class then Myer’s cube. See previous note re Boyer and Trump. <br>The smallest normal pandiagonal magic cube is order 7. See Pandiagonal magic cube.<br>Minimum correct summations required = 9"m" + 4. All pan-"r"-agonals sum correctly for "r" = 1 and 2. ALL 3"m" planar arrays must be pandiagonal magic squares. In addition, ALL pantriagonals must sum correctly. These two conditions combine to provide a total of 9m pandiagonal magic squares. <br>The smallest normal perfect magic cube is order 8. See