An Airpath compass

[longline]

appeared in a plastic box for Christmas. All taken apart.... I can figure out everything except the little bitty spring floating around in the bottom of said box. It is about 1/8 inch in diameter and maybe 1/4 inch long. Any hints?

 

[PaulT]

It's the jewel spring. Goes in the jewel post. Spring, Jewel, Post Cap.
Cheers