Licks, H. E · New York, D. Van Nostrand company · leaf 155
r reduced scale is the simplest apparatus in which one point always moves parallel to another. Fig. 58 shows its sim- plest form, ABCD being a paral- lelogram with joints at the corners and fastened to the paper at A. The straight rod EFP is fixed to AD at E and can slide longitudi- nally along a… … in a straight line to A. The bar ED slides at D in the fixed Fig. 59 groove DB along a straight line which always-passes through the fixed point A,'and the length AC equals EC or CD. As the point C is made to rotate about A in a circle Cc the end D slides, along the
Mathematical recreations
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