It's a little jigger. He indicated the first joint of his thumb.

Or if it is a yawl, then you would have a little jigger-mast astern-aboutthere--'

I'm taking this little jigger out of the distributer, so no one could run the old bus anyway.

Take you all round, and round it is, you 're a rum 'un, my lad-thequeerest little jigger that ever lay out on a royal-yard