volumescope

Century Dictionary and Cyclopedia

1. n. A graduated glass tube for demonstrating the difference in volume of the components of a compound, especially when they are set free by chemical action.

Wiktionary

1. n. An instrument consisting of a glass tube with a graduated scale that shows the changes in volume of a gas or gaseous mixture.

GNU Webster's 1913

1. n. (Physics) An instrument consisting essentially of a glass tube provided with a graduated scale, for exhibiting to the eye the changes of volume of a gas or gaseous mixture resulting from chemical action, etc.