What are the hollow glass i have that in a box with a hemacytometer?

i know a hemacytometer is used for counting individua cells, but i was wondering about the galss tubes in the case and what they are used for. they are different sizes and kind of look like thermometer with a bubble in the center.each bubble has a small glass bead in it which i would think to hinder the flow of somthing, I’m guessing. i’m thinking about selling on ebay, so if you want this let me know, cuase i have no use for it