premise: the <mask> of arms; the <mask> of the sword; the <mask> of the piece (cannon, mortar, etc.).
hypothesis: the best context for <mask> here is A prescribed exercise in the systematic handing of a weapon; but not A solid body which may be generated by the rotation of a parallelogram round one its sides; or a body of rollerlike form, of which the longitudinal section is oblong, and the cross section is circular..