This page needs to be proofread.
ISOSCELES DOUBLE-CRANKS.
293
d and b instead of between a andc; or the pair- closure may be partly between a and c and partly between d and b, but this gives us no new results.
FIG. 211.
The chain gives us two kinds of n-echanisms, one by placing it on d or a, the other by placing it on c or b.
FIG. 212.
The mechanism of Fig. 211, which is placed on d, has the formula (C"^C'f. The motion of c is remarkable, for it now not merely swings but completely revolves, and it has a mean
