1. This rule has a fairly standard arrangement of the scales, including 2 log-log scales on the stock and trig scales on the back of the slide. This may seem rather boring until one takes into account the fact that Thornton held a patent for differential trig and log-log scales. In the case of trig scales they enabled a wider range of values of both trig and inverse trig functions to be fitted into a smaller space. In the case of the log-log scales it enabled the range normally covered by LL0 and LL1 scales to be replaced by a single short scale. In both cases the drawback was the requirement for more slide movement. One can only assume that this rule was produced for users who were taught to use rules with more standard scales.