RDG006012 Unique devices have been developed for the study of the mechanisms that maintain the balance of energy in the human body, and for evaluation of thermal stress and measures to protect man against it. A microcalorimeter, one of the sensitive measuring devices pioneered and developed by NMRIs Director of Bioenergies, is seen in this photograph. This instrument is capable of measuring heat in quantitites as minute as 1/1,00 of a calorie, and temperature changes as low as 1/1,00,00 of a degree Centigrade.