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 70
F R^ the sideF Ri is common, angles <^ equal and side R^ T^ equal to side R F; the line R T^ is thereforeparallel to Ri F, whence angle T^ R F must also equal <^. In the triangle R F R^ we denote by 6 180° —<iy the angles opposite the equal sides RF and R^F; then JB + 4>^ 1S0° or 6 = 2… … 186. The Involute. As the opposite extreme of a circle rolling on a straight line we may havethe latter rolHng on a circle. In this case the rolling circle has an infinite radius. A point on thestraight line describes a curve called the involute. This would be the path of the end of a threadif the…
Mechanical drawing · Lettering
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
![An illustration from A treatise describing and explaining the construction and use of new celestial and terrestial globes; designed to illustrate ... the phoenomena [sic] of the earth and heavens, and to shew the correspondence of the two spheres. With a great variety of astronomical and geographical problems occasionally interspersed (1766)](https://img.insideoutlibrary.com/img/200/ia-treatisedescribi00adam-116-8.webp)
