In two previous articles in School and Society the writer pointed out that education was the one major activity in this country which had thus far not systematically applied ingenuity to the solution of its problems; and he attempted to illustrate, by two sample devices, how simple machines 'might both score tests and - with certain types of material - actually teach. In this third and last article of the series, two further attempts at laborsaving devices in education will be briefly described and an attempt made to evaluate the present Situation and future possibilities of work along these lines.