Chemical burn Chemical burn A chemical burn occurs when living tissue is exposed to a corrosive substance such as a strong acid or base. Chemical burns follow standard burn classification and may cause extensive tissue damage. The main types of irritant and/or corrosive products are: acids, bases, oxidizers / reducing agents, solvents, and alkylants. Additionally, chemical burns can be caused by some types of chemical weapons, e.g., vesicants such as mustard gas and Lewisite, or urticants such as phosgene oxime. Chemical burns may: The exact symptoms of a chemical burn depend on the chemical involved. Symptoms include itching, bleaching or darkening of
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