The other treatises included in Pappus's account are (1) On _Determinate Section_; (2) _Contacts_ or _Tangencies_, Book II of which is entirely devoted to the problem of drawing a circle to touch three given circles (Apollonius's solution can, with the aid of Pappus's auxiliary propositions, be satisfactorily restored); (3) _Plane Loci_, i. e. loci which are straight lines or circles; (4) Νευσεις {Neuseis}, _Inclinationes_ (the general problem called a νευσις {neusis} being to insert between two lines, straight or curved, a straight line of given length _verging_ to a given point, i. e. so that, if produced, it passes through the point, Apollonius restricted himself to cases which could be solved by 'plane' methods, i. e. by the straight line and circle only). Apollonius is also said to have written (5) a _Comparison of the dodecahedron with the icosahedron_ (inscribed in the same sphere), in which he proved that their surfaces are in the same ratio as their volumes; (6) _On the cochlias_ or cylindrical helix; (7) a 'General Treatise', which apparently dealt with the fundamental assumptions, &c., of elementary geometry; (8) a work on _unordered irrationals_, i. e. irrationals of more complicated form than those of Eucl. Book X; (9) _On the burning-mirror_, dealing with spherical mirrors and probably with mirrors of parabolic section also; (10) ωκυτοκιον {ôkytokion} ('quick delivery'). In the last-named work Apollonius found an approximation to π {p} closer than that in Archimedes's _Measurement of a Circle_; and possibly the book also contained Apollonius's exposition of his notation for large numbers according to 'tetrads' (successive powers of the myriad). In astronomy Apollonius is said to have made special researches regarding the moon, and to have been called ε {e} (Epsilon) because the form of that letter is associated with the moon. He was also a master of the theory of epicycles and eccentrics. With Archimedes and Apollonius Greek geometry reached its culminating point; indeed, without some more elastic notation and machinery such as algebra provides, geometry was practically at the end of its resources. For some time, however, there were capable geometers who kept up the tradition, filling in details, devising alternative solutions of problems, or discovering new curves for use or investigation.