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 Perfect magic cube. Nasik; A. H. Frost (1866) referred to all but the simple magic cube as Nasik!<br> C. Planck (1905) redefined "Nasik" to mean magic hypercubes of any order or dimension in which all possible lines summed correctly.<br> i.e. Nasik is a preferred alternate, and less ambiguous term for the "perfect" class.<br>Minimum correct summations required = 13"m". All pan-"r"-agonals sum correctly for "r" = 1, 2 and 3. Alternate Perfect Note that the above is a relatively new definition of "perfect". Until about 1995 there was much confusion about what constituted a "perfect" magic cube (see the discussion under