¹ This pure and therefore sublime science seems to forfeit something of its dignity in conceding that, as elementary geometry, it requires implements for the construction of its concepts, albeit only two, namely the compass and the ruler; these constructions alone are called ‘geometrical’, while those of higher geometry are called ‘mechanical’ because more complex mechanical devices are required to construct the concepts of the latter. But what we understand in the former case is not the actual implements (circinus et regola),* which can never render the relevant figures with mathematical precision, but rather the simplest ways in which the imagination can exhibit the latter a priori, something which cannot be matched by any instrument.