What is "graduated cap"

Graduated \Grad"u*a"ted\, a.

1. Marked with, or divided into, degrees; divided into grades.

2. (Zo["o]l.) Tapered; -- said of a bird's tail when the outer feathers are shortest, and the others successively longer.

3. Having visible marks and numbers at vertical intervals, permitting one to estimate the quantitity of material contained; -- of vessels, most commonly those used in laboratories for containing liquids. See graduated cylinder, etc., below.

   Graduated cylinder, Graduated flask, Graduated tube, Graduated bottle, Graduated cap, Graduated glass a vessel, usually of glass, having horizontal marks upon its sides, with figures, to indicate the amount of the contents at the several levels.

   Graduated spring (Railroads), a combination of metallic and rubber springs.