Practical plane and solid geometry for advanced students, including graphic statics, adapted to the requirements of the South Kensington syllabus (1899)
Harrison, Joseph, Baxandall, George Albert · London Macmillan · leaf 96
= constant. 2 a and also that CA - CB OP = OP1 = OP0 = = constant. Further, since both the triangles PfDP, PQOP areisosceles, it is evident that CO and OP are always equallyand symmetrically inclined to CA ; they are also equallyand symmetrically inclined to CB. We are thus led to thefollowing… … of which the principal axes are lines through C parallel andperpendicular to the fixed line, the lengths of the semi-axesbeing respectively equal to the sum and difference of CO andOP. A mechanism for draining ellipses has been constructedon this principle. CO is a crank free to rotate on a…
