The calibration of the calorimeter was performed by 10 combustion experiments of K-1 benzoic acid provided by the D.I. Mendeleev All-Russian Research Institute of Metrology with a certified energy of combustion, under bomb conditions, of (26454.4 ± 2.2) J g1 (the uncertainty for combustion energy of benzoic acid correspond to expanded uncertainty of the mean (0.95 level of confidence). From ten calibration experiments, the energy equivalent (ecalor) of the calorimeter was determined (76391.5 ± 12.0) J X1 , where the uncertainty quoted is the standard deviation of the mean.