A Plane's Aspect

Abstract

THE words “aspect” and “slope” have already a use in relation to the position of planes. They indicate two elements which together fix the position. Neither of them, taken alone, can indicate the position of a plane, unless a new and artificial meaning be assigned to one or other. Thus if I speak of the “aspect” of one of the faces of a roof as southerly, I have done something but not all that is necessary, towards describing the position of that face; if I add further that the “slope” is 30° I have definitely assigned the position. Again if I speak of the “slope” of Saturn's rings as 28° (the plane of reference being ecliptic), I have done something towards the description of their position if I add further that their “aspect” is toward such and such a degree of the sign Gemini, I fully assign their position in space. And so on.