what is it?

[lastonesitting]

picked up this item and have no earthly idea what it was
used for or even what it is...round glass tube with
gold or brass flakes in it that has a dial #ed 1-60
and pointer that spins....has two long split-sticks
from one end[Bakelite or ebony?]that are exactly 17"
long...at other end a handle with a loose spring that
allows object to dangle....see pics...any info would
be appreciated..thx, george