On a method of expressing by signs the action of machinery

In the construction of an engine for calculating and printing mathematical tables, in which the author of this paper has been for some time occupied, he states himself to have met with considerable difficulty from the want of any method by which all those motions which take place in any machine at the same instant, may be easily perceived and referred to, and by which the movement of any part might readily be traced back, through all the intervening stages, up to the first mover of the machine. The usual modes of mechanical drawing he found quite insufficient for these purposes, except in machinery of the simplest construction; and, even if they had not altogether failed in more complicated cases, the time and expense required for their execution would have effectually prevented their employment. The most important question was to contrive some method by which all the simultaneous movements, occurring at any moment, should be at once visible; and the history of the state of motion or rest of any given part should be apparent during the whole cycle of the action of the engine. The author had therefore recourse to a system of signs, which bear an analogy to those employed in algebra, whilst they differ from them by having a general resemblance to the things they are intended to represent. Having gradually found that this system, which he calls “ mechanical notation,” was readily susceptible of affording other information than that for which it was at first contrived, he was led to give to it additional extension.