4. The whole circumference is to 360 deg. as the length of arc a'e' is
to the angle oscillation of C divided by 2.
5. Half angle oscillation, C, taken from angle BAa' is equal to angle
BAc'.
6. Half angle oscillation, D, taken from angle ABa is equal to angle
ABb.
7. The diagonal of the rectangle formed by the (sum of the sines of
the angles of the arms with AB) into (AB--sum of cosines of same) will
be the length of link, E.
[Illustration]
G. R. NASH, Civil Engineer.
North Adams, Mass.
[We have received other solutions of this problem, but as this covers
the ground in a very simple manner, we think it will be sufficient.
Those forwarding the solutions not published will accept our thanks
and assurances that it is not because they lack merit that they are
declined.--EDS.
* * * * *