String on three parallel threads a number of small wooden scales,
somewhat thick in the middle, and rounded at the edges, to form a length
tapering to a point, while the other end is furnished with a carved head
as of a serpent. Fasten the threads so that they are moderately tight.
When taken up by the middle horizontally the two ends have a tendency to
sink, but being prevented by the connection, they move to one side or
the other. They can also be made of flat pieces, with one thread running
straight through all to form a length, and a thread to run through them
all alternately on one side and the other, opposite each other. If
turned, boxwood is better than ivory, which easily breaks.
[Illustration: Fig. 153.]
[Illustration]