Volume calibration of various gasmeters using a modified Tissot spirometer.

Various methods for determinating energy expenditure by indirect calorimetry are used in laboratory and field studies such as the Douglas bag method, often used in combination with a wet gasmeter, the respirometer of Kofranyi and Michaelis (KM) and the Oxylog (OX). To calibrate the volume measurements of these pieces of apparatus a modified Tissot spirometer was built, consisting of an outer casing filled with water, a core and a bell. It was equipped with a solid counterbalance and with an additional roller chain, partly freely suspended on the side of the counterbalance.