2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/35788Bartnik's definition of gravitational quasilocal energy is analyzed. For a wide class of systems Bartnik's function is given by the ADM mass of some vacuous extension. As an example we calculate mass of a non central ball in Schwarzschild geometry. The ratio mass to volume becomes singular in the limit of small volumes.11 pages, LeTex fileGeneral Relativity and Quantum Cosmologytext