Practical engineering drawing and third angle projection, for students in scientific, technical and manual training schools and for ... draughtsmen .. (1897)
Willson, Frederick Newton, 1855-1939 · Princeton, N.J., The author · leaf 43
e\-ident from inspection; while on the eleva- • These curves can also be obtained by assuming two foci, as if for an ellipse, but taking the product of the focal radii asa constant ciuantily, some perfect square. If pp= 36 then a point on the curve would be found at the intersection of arcshaving… … a(«)2(n) Urt) 32 31
Mechanical drawing · Lettering
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
![An illustration from [Electric engineering.] (1902)](https://img.insideoutlibrary.com/img/200/ia-electricengineer02inte-36-4.webp)
